Sunday, November 1, 2009

Ais Romney 2006 Slides 05 Computer Fraud And Abuse

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Ais Romney 2006 Slides 05 Computer Fraud And Abuse - Presentation Transcript

HAPTER 5 Computer Fraud and Security
INTRODUCTION
Questions to be addressed in this chapter:
What is fraud, and how are frauds perpetrated?
Who perpetrates fraud and why?
What is computer fraud, and what forms does it take?
What approaches and techniques are used to commit computer fraud?
INTRODUCTION
Information systems are becoming increasingly more complex and society is becoming increasingly more dependent on these systems.
Companies also face a growing risk of these systems being compromised.
Recent surveys indicate 67% of companies suffered a security breach in the last year with almost 60% reporting financial losses.
INTRODUCTION
Companies face four types of threats to their information systems:
Natural and political disasters
Include:
Fire or excessive heat
Floods
Earthquakes
High winds
War and terrorist attack
When a natural or political disaster strikes, many companies can be affected at the same time.
Example: Bombing of the World Trade Center in NYC.
The Defense Science Board has predicted that attacks on information systems by foreign countries, espionage agents, and terrorists will soon be widespread.
INTRODUCTION
Companies face four types of threats to their information systems:
Natural and political disasters
Software errors and equipment malfunction
Include:
Hardware or software failures
Software errors or bugs
Operating system crashes
Power outages and fluctuations
Undetected data transmission errors
Estimated annual economic losses due to software bugs = $60 billion.
60% of companies studied had significant software errors in previous year.
INTRODUCTION
Companies face four types of threats to their information systems:
Natural and political disasters
Software errors and equipment malfunction
Unintentional acts
Include
Accidents caused by:
Human carelessness
Failure to follow established procedures
Poorly trained or supervised personnel
Innocent errors or omissions
Lost, destroyed, or misplaced data
Logic errors
Systems that do not meet needs or are incapable of performing intended tasks
Information Systems Security Assn. estimates 65% of security problems are caused by human error.
INTRODUCTION
Companies face four types of threats to their information systems:
Natural and political disasters
Software errors and equipment malfunction
Unintentional acts
Intentional acts (computer crime)
Include:
Sabotage
Computer fraud
Misrepresentation, false use, or unauthorized disclosure of data
Misappropriation of assets
Financial statement fraud
Information systems are increasingly vulnerable to these malicious attacks.
INTRODUCTION
In this chapter we’ll discuss:
The fraud process
Why fraud occurs
Approaches to computer fraud
Specific techniques used to commit computer fraud
Ways companies can deter and detect computer fraud
INTRODUCTION
In this chapter we’ll discuss:
The fraud process
Why fraud occurs
Approaches to computer fraud
Specific techniques used to commit computer fraud
Ways companies can deter and detect computer fraud
THE FRAUD PROCESS
Fraud is any and all means a person uses to gain an unfair advantage over another person.
In most cases, to be considered fraudulent, an act must involve:
A false statement (oral or in writing)
About a material fact
Knowledge that the statement was false when it was uttered (which implies an intent to deceive)
A victim relies on the statement
And suffers injury or loss as a result
The definition is the same whether it is a criminal or civil fraud case.
The only difference is the burden of proof required.
Criminal case: Beyond a reasonable doubt.
Civil case: Preponderance of the evidence OR clear and convincing evidence.
THE FRAUD PROCESS
Since fraudsters don’t make journal entries to record their frauds, we can only estimate the amount of losses caused by fraudulent acts:
The Association of Certified Fraud Examiners (ACFE) estimates that total fraud losses in the U.S. run around 6% of annual revenues or approximately $660 billion in 2004.
More than we spend on education and roads in a year.
6 times what we pay for the criminal justice system.
Income tax fraud (the difference between what taxpayers owe and what they pay to the government) is estimated to be over $200 billion per year.
Fraud in the healthcare industry is estimated to exceed $100 billion a year.
THE FRAUD PROCESS
Fraud against companies may be committed by an employee or an external party.
Former and current employees (called knowledgeable insiders ) are much more likely than non-employees to perpetrate frauds (and big ones) against companies.
Largely owing to their understanding of the company’s systems and its weaknesses, which enables them to commit the fraud and cover their tracks.
Organizations must utilize controls to make it difficult for both insiders and outsiders to steal from the company.
THE FRAUD PROCESS
Fraud perpetrators are often referred to as white-collar criminals .
Distinguishes them from violent criminals, although some white-collar crime can ultimately have violent outcomes, such as:
Perpetrators or their victims committing suicide.
Healthcare patients killed because of alteration of information, etc., that can result in their deaths.
Types of Frauds
OCCUPATIONAL
Fraudulent Statements
Financial
Non-financial
Asset Misappropriation
Theft of Cash
Fraudulent disbursements
Inventory and other assets
Bribery and Corruption
Bribery
Illegal gratuities
Economic extortion
Conflict of interest
OTHER
Intellectual property theft
Financial institution fraud
Check and credit card fraud
Insurance fraud
Healthcare fraud
Bankruptcy fraud
Tax fraud
Securities fraud
Money laundering
Consumer fraud
Computer and Internet fraud
Information is from the ACFE’s 2004 Report to the Nation on Occupational Fraud and Abuse and from the Fraud Examiner’s Manual , also published by the ACFE.
THE FRAUD PROCESS
Three types of occupational fraud:
Misappropriation of assets
Involves theft, embezzlement, or misuse of company assets for personal gain.
Examples include billing schemes, check tampering, skimming, and theft of inventory.
In the 2004 Report to the Nation on Occupational Fraud and Abuse , 92.7% of occupational frauds involved asset misappropriation at a median cost of $93,000.
THE FRAUD PROCESS
Three types of occupational fraud:
Misappropriation of assets
Corruption
Corruption involves the wrongful use of a position, contrary to the responsibilities of that position, to procure a benefit.
Examples include kickback schemes and conflict of interest schemes.
About 30.1% of occupational frauds include corruption schemes at a median cost of $250,000.
THE FRAUD PROCESS
Three types of occupational fraud:
Misappropriation of assets
Corruption
Fraudulent statements
Financial statement fraud involves misstating the financial condition of an entity by intentionally misstating amounts or disclosures in order to deceive users.
Financial statements can be misstated as a result of intentional efforts to deceive or as a result of undetected asset misappropriations that are so large that they cause misstatement.
About 7.9% of occupational frauds involve fraudulent statements at a median cost of $1 million. (The median pales in comparison to the maximum cost.)
THE FRAUD PROCESS
A typical employee fraud has a number of important elements or characteristics:
The fraud perpetrator must gain the trust or confidence of the person or company being defrauded in order to commit and conceal the fraud.
Instead of using a gun, knife, or physical force, fraudsters use weapons of deceit and misinformation.
Frauds tend to start as the result of a perceived need on the part of the employee and then escalate from need to greed. Most fraudsters can’t stop once they get started, and their frauds grow in size.
The fraudsters often grow careless or overconfident over time.
Fraudsters tend to spend what they steal. Very few save it.
In time, the sheer magnitude of the frauds may lead to detection.
The most significant contributing factor in most employee frauds is the absence of internal controls and/or the failure to enforce existing controls.
THE FRAUD PROCESS
The National Commission on Fraudulent Financial Reporting ( aka, the Treadway Commission) defined fraudulent financial reporting as intentional or reckless conduct, whether by act or omission, that results in materially misleading financial statements.
Financial statements can be falsified to:
Deceive investors and creditors
Cause a company’s stock price to rise
Meet cash flow needs
Hide company losses and problems
THE FRAUD PROCESS
Fraudulent financial reporting is of great concern to independent auditors, because undetected frauds lead to half of the lawsuits against auditors.
In the case of Enron, a financial statement fraud led to the total elimination of Arthur Andersen, a premiere international public accounting firm.
THE FRAUD PROCESS
Common approaches to “cooking the books” include:
Recording fictitious revenues
Recording revenues prematurely
Recording expenses in later periods
Overstating inventories or fixed assets (WorldCom)
Concealing losses and liabilities
THE FRAUD PROCESS
The Treadway Commission recommended four actions to reduce the possibility of fraudulent financial reporting:
Establish an organizational environment that contributes to the integrity of the financial reporting process.
Identify and understand the factors that lead to fraudulent financial reporting.
Assess the risk of fraudulent financial reporting within the company.
Design and implement internal controls to provide reasonable assurance that fraudulent financial reporting is prevented.
THE FRAUD PROCESS
SAS 99: The Auditor’s Responsibility to Detect Fraud
In 1997, SAS-82, Consideration of Fraud in a Financial Statement Audit , was issued to clarify the auditor’s responsibility to detect fraud.
THE FRAUD PROCESS
A revision to SAS-82, SAS-99, was issued in December 2002. SAS-99 requires auditors to:
Understand fraud
Auditors can’t effectively audit something they don’t understand.
SAS-99 also indicated that auditors are not lawyers and “do not make legal determinations of whether fraud has occurred.”
The external auditor’s interest specifically relates to acts that result in a material misstatement of the financial statements.
Note that SAS-99 relates to external auditors. Internal auditors will have a more extensive interest in fraud than just those that impact financial statements.
THE FRAUD PROCESS
A revision to SAS-82, SAS-99, was issued in December 2002. SAS-99 requires auditors to:
Understand fraud
Discuss the risks of material fraudulent misstatements
While planning the audit, members of the audit team should discuss how and where the company’s financial statements might be susceptible to fraud.
THE FRAUD PROCESS
A revision to SAS-82, SAS-99, was issued in December 2002. SAS-99 requires auditors to:
Understand fraud
Discuss the risks of material fraudulent misstatements
Obtain information
The audit team must gather evidence about the existence of fraud by:
Looking for fraud risk factors
Testing company records
Asking management, the audit committee, and others if they know of any past or current fraud or of fraud risks the organization faces.
Special care needs to be exercised in examining revenue accounts, since they are particularly popular fraud targets.
THE FRAUD PROCESS
A revision to SAS-82, SAS-99, was issued in December 2002. SAS-99 requires auditors to:
Understand fraud
Discuss the risks of material fraudulent misstatements
Obtain information
Identify, assess, and respond to risks
Use the gathered information to identify, assess, and respond to risks.
Auditors can respond by varying the nature, timing, and extent of auditing procedures they perform.
They should also carefully evaluate risks related to management override of controls.
THE FRAUD PROCESS
A revision to SAS-82, SAS-99, was issued in December 2002. SAS-99 requires auditors to:
Understand fraud
Discuss the risks of material fraudulent misstatements
Obtain information
Identify, assess, and respond to risks
Evaluate the results of their audit tests
Auditors must assess the risk of fraud throughout the audit.
When the audit is complete, they must evaluate whether any identified misstatements indicate the presence of fraud.
If so, they should determine the impact on the financial statements and the audit.
THE FRAUD PROCESS
A revision to SAS-82, SAS-99, was issued in December 2002. SAS-99 requires auditors to:
Understand fraud
Discuss the risks of material fraudulent misstatements
Obtain information
Identify, assess, and respond to risks
Evaluate the results of their audit tests
Communicate findings
Auditors communicate their fraud findings to management, the audit committee, and others.
THE FRAUD PROCESS
A revision to SAS-82, SAS-99, was issued in December 2002. SAS-99 requires auditors to:
Understand fraud
Discuss the risks of material fraudulent misstatements
Obtain information
Identify, assess, and respond to risks
Evaluate the results of their audit tests
Communicate findings
Document their audit work
Auditors must document their compliance with SAS-99 requirements.
THE FRAUD PROCESS
A revision to SAS-82, SAS-99, was issued in December 2002. SAS-99 requires auditors to:
Understand fraud
Discuss the risks of material fraudulent misstatements
Obtain information
Identify, assess, and respond to risks
Evaluate the results of their audit tests
Communicate findings
Document their audit work
Incorporate a technology focus
SAS-99 recognizes that technology impacts fraud risks and notes opportunities that auditors have to use technology-oriented tools and techniques to design fraud auditing procedures.
INTRODUCTION
In this chapter we’ll discuss:
The fraud process
Why fraud occurs
Approaches to computer fraud
Specific techniques used to commit computer fraud
Ways companies can deter and detect computer fraud
WHO COMMITS FRAUD AND WHY
Researchers have compared the psychological and demographic characteristics of three groups of people:
White-collar criminals
Violent criminals
The general public
They found:
Significant differences between violent and white-collar criminals.
Few differences between white-collar criminals and the general public.
WHO COMMITS FRAUD AND WHY
White-collar criminals tend to mirror the general public in:
Education
Age
Religion
Marriage
Length of employment
Psychological makeup
WHO COMMITS FRAUD AND WHY
Perpetrators of computer fraud tend to be younger and possess more computer knowledge, experience, and skills.
Hackers and computer fraud perps tend to be more motivated by:
Curiosity
A quest for knowledge
The desire to learn how things work
The challenge of beating the system
WHO COMMITS FRAUD AND WHY
They may view their actions as a game rather than dishonest behavior.
Another motivation may be to gain stature in the hacking community.
Some see themselves as revolutionaries spreading a message of anarchy and freedom.
But a growing number want to profit financially. To do so, they may sell data to:
Spammers
Organized crime
Other hackers
The intelligence community
WHO COMMITS FRAUD AND WHY
Some fraud perpetrators are disgruntled and unhappy with their jobs and are seeking revenge against their employers.
Others are regarded as ideal, hard-working employees in positions of trust.
Most have no prior criminal record.
So why are they willing to risk everything?
WHO COMMITS FRAUD AND WHY
Criminologist Donald Cressey, interviewed 200+ convicted white-collar criminals in an attempt to determine the common threads in their crimes. As a result of his research, he determined that three factors were present in the commission of each crime. These three factors have come to be known as the fraud triangle.
Pressure
Opportunity
Rationalization
The “Fraud Triangle” Donald Cressey Pressure Opportunity Rationalization
The “Fraud Triangle” Donald Cressey Pressure Opportunity Rationalization
WHO COMMITS FRAUD AND WHY
Pressure
Cressey referred to this pressure as a “perceived non-shareable need.”
The pressure could be related to finances, emotions, lifestyle, or some combination.
WHO COMMITS FRAUD AND WHY
The most common pressures were:
Not being able to pay one’s debts, nor admit it to one’s employer, family, or friends (which makes in non-shareable )
May be associated with vices, such as drugs, gambling, mistresses, etc.
WHO COMMITS FRAUD AND WHY
The most common pressures were:
Not being able to pay one’s debts, nor admit it to one’s employer, family, or friends (which makes in non-shareable)
Fear of loss of status because of a personal failure
Example would be mismanagement of a personal investment or retirement fund.
WHO COMMITS FRAUD AND WHY
The most common pressures were:
Not being able to pay one’s debts, nor admit it to one’s employer, family, or friends (which makes in non-shareable)
Fear of loss of status because of a personal failure
Business reversals
Not many people can walk away from a failing business.
WHO COMMITS FRAUD AND WHY
The most common pressures were:
Not being able to pay one’s debts, nor admit it to one’s employer, family, or friends (which makes in non-shareable)
Fear of loss of status because of a personal failure
Business reversals
Physical isolation
When an individual is isolated, physically or psychologically, almost any pressure becomes non-shareable.
WHO COMMITS FRAUD AND WHY
The most common pressures were:
Not being able to pay one’s debts, nor admit it to one’s employer, family, or friends (which makes in non-shareable)
Fear of loss of status because of a personal failure
Business reversals
Physical isolation
Status gaining
Many frauds are motivated by nothing more than a perceived need to keep up with the Joneses.
The problem is that there is always a richer “Jones” down the street and the pressure continues to mount, as do the resulting thefts.
WHO COMMITS FRAUD AND WHY
The most common pressures were:
Not being able to pay one’s debts, nor admit it to one’s employer, family, or friends (which makes in non-shareable)
Fear of loss of status because of a personal failure
Business reversals
Physical isolation
Status gaining
Difficulties in employer-employee relations
May create pressure to get revenge, take the money you feel is rightfully owed to you, etc.
WHO COMMITS FRAUD AND WHY
What’s important here is the perception of the pressure .
There might be a number of people who could and would help a tentative fraudster out of his financial woes.
But as long as he perceives that he cannot share his burden, the pressure is present.
Research has also found that an individual’s propensity to commit fraud is more related to how much he worries about his financial position than his actual position.
The millionaire who frets a lot about his financial condition is more likely to commit fraud than the guy who doesn’t have two dimes to rub together but isn’t worried about it.
WHO COMMITS FRAUD AND WHY
Financial statement fraud is distinct from other types of fraud in that the individuals who commit the fraud are not the direct beneficiaries.
The company is the direct beneficiary.
The perpetrators are typically indirect beneficiaries.
WHO COMMITS FRAUD AND WHY
In the case of financial statement frauds, common pressures include:
To prop up earnings or stock price so that management can:
Receive performance-related compensation.
Preserve or improve personal wealth held in company stock or stock options.
Keep their jobs.
To cover the inability to generate cash flow.
To obtain financing.
To appear to comply with bond covenants or other agreements.
May be opposite of propping up earnings in cases involving income-tax motivations, government contracts, or regulation.
Click here for a comprehensive list of pressures .
Pressures
PRESSURES THAT LEAD TO EMPLOYEE FRAUD
FINANCIAL
Living beyond means
High personal debt/expenses
“ Inadequate” salary/income
Poor credit ratings
Heavy financial losses
Bad investments
Tax avoidance
Meet unreasonable quotas/goals
EMOTIONAL
Greed
Unrecognized performance
Job dissatisfaction
Fear of losing job
Power or control
Pride or ambition
Beating the system
Frustration
Non-conformity
Envy, resentment
Arrogance, dominance
Non-rules oriented
LIFESTYLE
Support gambling habit
Drug or alcohol addiction
Support sexual relationships
Family/peer pressure
The “Fraud Triangle” Donald Cressey Pressure Opportunity Rationalization
WHO COMMITS FRAUD AND WHY
Opportunity is the opening or gateway that allows an individual to:
Commit the fraud
Conceal the fraud
Convert the proceeds
WHO COMMITS FRAUD AND WHY
Opportunity is the opening or gateway that allows an individual to:
Commit the fraud
Conceal the fraud
Convert the proceeds
WHO COMMITS FRAUD AND WHY
Committing the fraud might involve acts such as:
Misappropriating assets.
Issuing deceptive financial statements.
Accepting a bribe in order to make an arrangement that is not in the company’s best interest.
WHO COMMITS FRAUD AND WHY
Opportunity is the opening or gateway that allows an individual to:
Commit the fraud
Conceal the fraud
Convert the proceeds
WHO COMMITS FRAUD AND WHY
Concealing the fraud often takes more time and effort and leaves more evidence than the actual theft or misrepresentation.
Examples of concealment efforts:
Charge a stolen asset to an expense account or to an account receivable that is about to be written off.
WHO COMMITS FRAUD AND WHY
Concealing the fraud often takes more time and effort and leaves more evidence than the actual theft or misrepresentation.
Examples of concealment efforts:
Charge a stolen asset to an expense account or to an account receivable that is about to be written off.
Create a ghost employee who receives an extra paycheck.
WHO COMMITS FRAUD AND WHY
Concealing the fraud often takes more time and effort and leaves more evidence than the actual theft or misrepresentation.
Examples of concealment efforts:
Charge a stolen asset to an expense account or to an account receivable that is about to be written off.
Create a ghost employee who receives an extra paycheck.
Lapping.
Steal a payment from Customer A.
Apply Customer B’s payment to Customer A’s account so Customer A won’t get a late notice.
Apply Customer C’s payment to Customer B’s account, so Customer B won’t get a late notice, etc.
WHO COMMITS FRAUD AND WHY
Concealing the fraud often takes more time and effort and leaves more evidence than the actual theft or misrepresentation.
Examples of concealment efforts:
Charge a stolen asset to an expense account or to an account receivable that is about to be written off.
Create a ghost employee who receives an extra paycheck.
Lapping.
Kiting.
Creates “cash” by transferring money between banks.
Requires multiple bank accounts.
Basic scheme:
Write a check on the account of Bank A.
Bank A doesn’t have sufficient funds to cover the check, so write a check from an account in Bank B to be deposited in Bank A.
Bank B doesn’t have sufficient funds to cover the check, so write a check from an account in Bank C to be deposited in Bank B, etc.
WHO COMMITS FRAUD AND WHY
Opportunity is the opening or gateway that allows an individual to:
Commit the fraud
Conceal the fraud
Convert the proceeds
WHO COMMITS FRAUD AND WHY
Unless the target of the theft is cash, then the stolen goods must be converted to cash or some form that is beneficial to the perpetrator.
Checks can be converted through alterations, forged endorsements, check washing, etc.
Non-cash assets can be sold (online auctions are a favorite forum) or returned to the company for cash.
WHO COMMITS FRAUD AND WHY
If the fraud is a financial statement fraud, then the gains received may include:
I got to keep my job.
The value of my stock or stock options rose.
I got a raise, promotion, or bonus.
I got power.
There are many opportunities that enable fraud. Some of the most common are:
Lack of internal controls
Failure to enforce controls (the most prevalent reason)
Excessive trust in key employees
Incompetent supervisory personnel
Inattention to details
Inadequate staff
Click here for a comprehensive list of opportunities.
WHO COMMITS FRAUD AND WHY Opportunities
OPPORTUNITIES PERMITTING EMPLOYEE AND FINANCIAL STATEMENT FRAUD
Internal Control Factors
Failure to enforce/monitor internal controls
Management not involved in control system
Management override of controls and guidelines
Managerial carelessness, inattention to details
Dominant and unchallenged management
Ineffective oversight by board of directors
No effective internal auditing staff
Infrequent third-party reviews
Insufficient separation of authorization, custody, and record-keeping duties
Too much trust in key employees
Inadequate supervision
Unclear lines of authority
OPPORTUNITIES PERMITTING EMPLOYEE AND FINANCIAL STATEMENT FRAUD
Lack of proper authorization procedures
No independent checks on performance
Inadequate documents and records
Inadequate system for safeguarding assets
No physical or logical security system
No audit trails
Failure to conduct background checks
No policy of annual vacations, rotation of duties
OPPORTUNITIES PERMITTING EMPLOYEE AND FINANCIAL STATEMENT FRAUD
Other Factors
Large, unusual, or complex transactions
Numerous adjusting entries at year end
Related-party transactions
Accounting department understaffed and overworked
Incompetent personnel
Rapid turnover of key employees
Lengthy tenure in a key job
Unnecessarily complex organizational structure
No code of conduct, conflict of interest statements, or definitions of unacceptable behavior
Frequently changing auditors, legal counsel
Operating on a crisis basis
Close association with suppliers/customers
OPPORTUNITIES PERMITTING EMPLOYEE AND FINANCIAL STATEMENT FRAUD
Assets highly susceptible to misappropriation
Questionable accounting practices
Pushing accounting principles to the limit
Unclear company policies and procedures
Failing to teach and stress corporate honesty
Failure to prosecute dishonest employees
Low employee morale and loyalty
WHO COMMITS FRAUD AND WHY
Internal controls that may be lacking or un-enforced include:
Authorization procedures
Clear lines of authority
Adequate supervision
Adequate documents and records
A system to safeguard assets
Independent checks on performance
Separation of duties
One control feature that many companies lack is a background check on all potential employees.
WHO COMMITS FRAUD AND WHY
Management may allow fraud by:
Not getting involved in the design or enforcement of internal controls;
Inattention or carelessness;
Overriding controls; and/or
Using their power to compel subordinates to carry out the fraud.
The “Fraud Triangle” Donald Cressey Pressure Opportunity Rationalization
WHO COMMITS FRAUD AND WHY
How many people do you know who regard themselves as being unprincipled or sleazy?
It is important to understand that fraudsters do not regard themselves as unprincipled.
In general, they regard themselves as highly principled individuals.
That view of themselves is important to them.
The only way they can commit their frauds and maintain their self image as principled individuals is to create rationalizations that recast their actions as “morally acceptable” behaviors.
WHO COMMITS FRAUD AND WHY
These rationalizations take many forms, including:
I was just borrowing the money.
It wasn’t really hurting anyone. (Corporations are often seen as non-persons, therefore crimes against them are not hurting “anyone.”)
Everybody does it.
I’ve worked for them for 35 years and been underpaid all that time. I wasn’t stealing; I was only taking what was owed to me.
I didn’t take it for myself. I needed it to pay my child’s medical bills.
WHO COMMITS FRAUD AND WHY
Creators of worms and viruses often use rationalizations like:
The malicious code helped expose security flaws, so I did a good service.
It was an accident.
It was not my fault—just an experiment that went bad.
It was the user’s fault because they didn’t keep their security up to date.
If the code didn’t alter or delete any of their files, then what’s the problem?
WHO COMMITS FRAUD AND WHY
Fraud occurs when:
People have perceived, non-shareable pressures ;
The opportunity gateway is left open; and
They can rationalize their actions to reduce the moral impact in their minds (i.e., they have low integrity).
Fraud is much less likely to occur when
There is low pressure, low opportunity, and high integrity.
Unfortunately, there is usually a mixture of these forces in play, and it can be very difficult to determine the pressures that may apply to an individual and the rationalizations he/she may be able to produce.
INTRODUCTION
In this chapter we’ll discuss:
The fraud process
Why fraud occurs
Approaches to computer fraud
Specific techniques used to commit computer fraud
Ways companies can deter and detect computer fraud
APPROACHES TO COMPUTER FRAUD
The U.S. Department of Justice defines computer fraud as any illegal act for which knowledge of computer technology is essential for its:
Perpetration;
Investigation; or
Prosecution.
APPROACHES TO COMPUTER FRAUD
Computer fraud includes the following:
Unauthorized theft, use, access, modification, copying, and destruction of software or data.
Theft of money by altering computer records.
Theft of computer time.
Theft or destruction of computer hardware.
Use or the conspiracy to use computer resources to commit a felony.
Intent to illegally obtain information or tangible property through the use of computers.
APPROACHES TO COMPUTER FRAUD
In using a computer, fraud perpetrators can steal:
More of something
In less time
With less effort
They may also leave very little evidence, which can make these crimes more difficult to detect.
APPROACHES TO COMPUTER FRAUD
Computer systems are particularly vulnerable to computer crimes for several reasons:
Company databases can be huge and access privileges can be difficult to create and enforce. Consequently, individuals can steal, destroy, or alter massive amounts of data in very little time.
Organizations often want employees, customers, suppliers, and others to have access to their system from inside the organization and without. This access also creates vulnerability.
Computer programs only need to be altered once, and they will operate that way until:
The system is no longer in use; or
Someone notices.
APPROACHES TO COMPUTER FRAUD
Modern systems are accessed by PCs, which are inherently more vulnerable to security risks and difficult to control.
It is hard to control physical access to each PC.
PCs are portable, and if they are stolen, the data and access capabilities go with them.
PCs tend to be located in user departments, where one person may perform multiple functions that should be segregated.
PC users tend to be more oblivious to security concerns.
APPROACHES TO COMPUTER FRAUD
Computer systems face a number of unique challenges:
Reliability (accuracy and completeness)
Equipment failure
Environmental dependency (power, water damage, fire)
Vulnerability to electromagnetic interference and interruption
Eavesdropping
Misrouting
APPROACHES TO COMPUTER FRAUD
Organizations that track computer fraud estimate that most U.S. businesses have been victimized by at least one incident of computer fraud.
APPROACHES TO COMPUTER FRAUD
These frauds cost billions of dollars each year, and their frequency is increasing because:
Not everyone agrees on what constitutes computer fraud.
Many don’t believe that taking an unlicensed copy of software is computer fraud. (It is and can result in prosecution.)
Some don’t think it’s a crime to browse through someone else’s computer if their intentions aren’t malicious.
APPROACHES TO COMPUTER FRAUD
Many computer frauds go undetected.
An estimated 80-90% of frauds that are uncovered are not reported because of fear of:
Adverse publicity
Copycats
Loss of customer confidence.
There are a growing number of competent computer users, and they are aided by easier access to remote computers through the Internet and other data networks.
APPROACHES TO COMPUTER FRAUD
Some folks believe “it can’t happen to us.”
Many networks have a low level of security.
Instructions on how to perpetrate computer crimes and abuses are readily available on the Internet.
Law enforcement is unable to keep up with the growing number of frauds.
The total dollar value of losses is difficult to calculate.
APPROACHES TO COMPUTER FRAUD
Economic espionage , the theft of information and intellectual property, is growing especially fast.
This growth has led to the need for investigative specialists or cybersleuths.
APPROACHES TO COMPUTER FRAUD
Computer Fraud Classification
Frauds can be categorized according to the data processing model:
Input
Processor
Computer instructions
Stored data
Output
COMPUTER FRAUD CLASSIFICATIONS Processor Fraud Input Fraud Output Fraud Data Fraud Computer Instructions Fraud
COMPUTER FRAUD CLASSIFICATIONS Processor Fraud Input Fraud Output Fraud Data Fraud Computer Instructions Fraud
APPROACHES TO COMPUTER FRAUD
Input Fraud
The simplest and most common way to commit a fraud is to alter computer input.
Requires little computer skills.
Perpetrator only need to understand how the system operates
Can take a number of forms, including:
Disbursement frauds
The perpetrator causes a company to:
Pay too much for ordered goods; or
Pay for goods never ordered.
APPROACHES TO COMPUTER FRAUD
Input Fraud
The simplest and most common way to commit a fraud is to alter computer input.
Requires little computer skills.
Perpetrator only need to understand how the system operates
Can take a number of forms, including:
Disbursement frauds
Inventory frauds
The perpetrator enters data into the system to show that stolen inventory has been scrapped.
APPROACHES TO COMPUTER FRAUD
Input Fraud
The simplest and most common way to commit a fraud is to alter computer input.
Requires little computer skills.
Perpetrator only need to understand how the system operates
Can take a number of forms, including:
Disbursement frauds
Inventory frauds
Payroll frauds
Perpetrators may enter data to:
Increase their salaries
Create a fictitious employee
Retain a terminated employee on the records.
In the latter two instances, the perpetrator intercepts and cashes the resulting paychecks.
APPROACHES TO COMPUTER FRAUD
Input Fraud
The simplest and most common way to commit a fraud is to alter computer input.
Requires little computer skills.
Perpetrator only need to understand how the system operates
Can take a number of forms, including:
Disbursement frauds
Inventory frauds
Payroll frauds
Cash receipt frauds
The perpetrator hides the theft by falsifying system input.
EXAMPLE: Cash of $200 is received. The perpetrator records a cash receipt of $150 and pockets the $50 difference.
APPROACHES TO COMPUTER FRAUD
Input Fraud
The simplest and most common way to commit a fraud is to alter computer input.
Requires little computer skills.
Perpetrator only need to understand how the system operates
Can take a number of forms, including:
Disbursement frauds
Inventory frauds
Payroll frauds
Cash receipt frauds
Fictitious refund fraud
The perpetrator files for an undeserved refund, such as a tax refund.
COMPUTER FRAUD CLASSIFICATIONS Processor Fraud Input Fraud Output Fraud Data Fraud Computer Instructions Fraud
APPROACHES TO COMPUTER FRAUD
Processor Fraud
Involves computer fraud committed through unauthorized system use.
Includes theft of computer time and services.
Incidents could involve employees:
Surfing the Internet;
Using the company computer to conduct personal business; or
Using the company computer to conduct a competing business.
APPROACHES TO COMPUTER FRAUD
In one example, an agriculture college at a major state university was experiencing very sluggish performance from its server.
Upon investigating, IT personnel discovered that an individual outside the U.S. had effectively hijacked the college’s server to both store some of his/her research data and process it.
The college eliminated the individual’s data and blocked future access to the system.
The individual subsequently contacted college personnel to protest the destruction of the data.
Demonstrates both:
How a processor fraud can be committed.
How oblivious users can sometimes be to the unethical or illegal nature of their activities.
COMPUTER FRAUD CLASSIFICATIONS Processor Fraud Input Fraud Output Fraud Data Fraud Computer Instructions Fraud
APPROACHES TO COMPUTER FRAUD
Computer Instructions Fraud
Involves tampering with the software that processes company data.
May include:
Modifying the software
Making illegal copies
Using it in an unauthorized manner
Also might include developing a software program or module to carry out an unauthorized activity.
APPROACHES TO COMPUTER FRAUD
Computer instruction fraud used to be one of the least common types of frauds because it required specialized knowledge about computer programming beyond the scope of most users.
Today these frauds are more frequent--courtesy of web pages that instruct users on how to create viruses and other schemes.
COMPUTER FRAUD CLASSIFICATIONS Processor Fraud Input Fraud Output Fraud Data Fraud Computer Instructions Fraud
APPROACHES TO COMPUTER FRAUD
Data Fraud
Involves:
Altering or damaging a company’s data files; or
Copying, using, or searching the data files without authorization.
In many cases, disgruntled employees have scrambled, altered, or destroyed data files.
Theft of data often occurs so that perpetrators can sell the data.
Most identity thefts occur when insiders in financial institutions, credit agencies, etc., steal and sell financial information about individuals from their employer’s database.
COMPUTER FRAUD CLASSIFICATIONS Processor Fraud Input Fraud Output Fraud Data Fraud Computer Instructions Fraud
APPROACHES TO COMPUTER FRAUD
Output Fraud
Involves stealing or misusing system output.
Output is usually displayed on a screen or printed on paper.
Unless properly safeguarded, screen output can easily be read from a remote location using inexpensive electronic gear.
This output is also subject to prying eyes and unauthorized copying.
Fraud perpetrators can use computers and peripheral devices to create counterfeit outputs, such as checks.
INTRODUCTION
In this chapter we’ll discuss:
The fraud process
Why fraud occurs
Approaches to computer fraud
Specific techniques used to commit computer fraud
Ways companies can deter and detect computer fraud
COMPUTER FRAUD AND ABUSE TECHNIQUES
Perpetrators have devised many methods to commit computer fraud and abuse. These include:
Data diddling
Changing data before, during, or after it is entered into the system.
Can involve adding, deleting, or altering key system data.
COMPUTER FRAUD AND ABUSE TECHNIQUES
Perpetrators have devised many methods to commit computer fraud and abuse. These include:
Data diddling
Data leakage
Unauthorized copying of company data.
COMPUTER FRAUD AND ABUSE TECHNIQUES
Perpetrators have devised many methods to commit computer fraud and abuse. These include:
Data diddling
Data leakage
Denial of service attacks
An attacker overloads and shuts down an Internet Service Provider’s email system by sending email bombs at a rate of thousands per second—often from randomly generated email addresses.
May also involve shutting down a web server by sending a load of requests for the web pages.
COMPUTER FRAUD AND ABUSE TECHNIQUES
Perpetrators have devised many methods to commit computer fraud and abuse. These include:
Data diddling
Data leakage
Denial of service attacks
Carried out as follows:
The attacker infects dozens of computers that have broadband Internet access with denial-of-service programs. These infected computers are the zombies .
The attacker then activates the denial-of-service programs, and the zombies send pings (emails or requests for data) to the target server. The victim responds to each, not realizing they have fictitious return addresses, and waits for responses that don’t come.
While the victim waits, system performance degrades until the system freezes up or crashes.
The attacker terminates the program after an hour or two to limit the victim’s ability to trace the source.
COMPUTER FRAUD AND ABUSE TECHNIQUES
Perpetrators have devised many methods to commit computer fraud and abuse. These include:
Data diddling
Data leakage
Denial of service attacks
Experts estimate there as many as 5,000 denial-of-service attacks weekly in the U.S.
A denial-of-service can cause severe economic damage to its victim or even drive them out of business.
COMPUTER FRAUD AND ABUSE TECHNIQUES
Perpetrators have devised many methods to commit computer fraud and abuse. These include:
Data diddling
Data leakage
Denial of service attacks
Eavesdropping
Perpetrators surreptitiously observe private communications or transmission of data.
Equipment to commit these “electronic wiretaps” is readily available at electronics stores.
COMPUTER FRAUD AND ABUSE TECHNIQUES
Perpetrators have devised many methods to commit computer fraud and abuse. These include:
Data diddling
Data leakage
Denial of service attacks
Eavesdropping
Email threats
A threatening message is sent to a victim to induce the victim to do something that would make it possible to be defrauded.
Several banks in the Midwest were contacted by an overseas perpetrator who indicated that:
He had broken into their computer system and obtained personal and banking information about all of the bank’s customers.
He would notify the bank’s customers of this breach if he was not paid a specified sum of money.
COMPUTER FRAUD AND ABUSE TECHNIQUES
Perpetrators have devised many methods to commit computer fraud and abuse. These include:
Data diddling
Data leakage
Denial of service attacks
Eavesdropping
Email threats
Email forgery (aka, spoofing )
Involves sending an email message that appears to have come from someone other than the actual sender.
Email spoofers may:
Claim to be system administrators and ask users to change their passwords to specific values.
Pretend to be management and request a copy of some sensitive information.
COMPUTER FRAUD AND ABUSE TECHNIQUES
Perpetrators have devised many methods to commit computer fraud and abuse. These include:
Data diddling
Data leakage
Denial of service attacks
Eavesdropping
Email threats
Email forgery (aka, spoofing )
Hacking
Unauthorized access to and use of computer systems—usually by means of a personal computer and a telecommunications network.
Most hackers break into systems using known flaws in operating systems, applications programs, or access controls.
Some are not very malevolent and mainly motivated by curiosity and a desire to overcome a challenge.
Others have malicious intent and can do significant damage.
COMPUTER FRAUD AND ABUSE TECHNIQUES
Perpetrators have devised many methods to commit computer fraud and abuse. These include:
Data diddling
Data leakage
Denial of service attacks
Eavesdropping
Email threats
Email forgery (aka, spoofing )
Hacking
Phreaking
Hacking that attacks phone systems and uses phone lines to transmit viruses and to access, steal, and destroy data.
They also steal telephone services and may break into voice mail systems.
Some hackers gain access to systems through dial-up modem lines.
COMPUTER FRAUD AND ABUSE TECHNIQUES
Perpetrators have devised many methods to commit computer fraud and abuse. These include:
Data diddling
Data leakage
Denial of service attacks
Eavesdropping
Email threats
Email forgery (aka, spoofing )
Hacking
Phreaking
Hijacking
Involves gaining control of someone else’s computer to carry out illicit activities without the user’s knowledge.
The illicit activity is often the perpetuation of spam emails.
COMPUTER FRAUD AND ABUSE TECHNIQUES
Perpetrators have devised many methods to commit computer fraud and abuse. These include:
Data diddling
Data leakage
Denial of service attacks
Eavesdropping
Email threats
Email forgery (aka, spoofing )
Hacking
Phreaking
Hijacking
Identity theft
Assuming someone’s identity, typically for economic gain, by illegally obtaining and using confidential information such as the person’s social security number, bank account number, or credit card number.
Identity thieves benefit financially by:
Taking funds out of the victim’s bank account.
Taking out mortgages or other loans under the victim’s identity.
Taking out credit cards and running up large balances.
If the thief is careful and ensures that bills and notices are sent to an address he controls, the scheme may be prolonged until such time as the victim attempts to buy a home or car and finds out that his credit is destroyed.
COMPUTER FRAUD AND ABUSE TECHNIQUES
Perpetrators have devised many methods to commit computer fraud and abuse. These include:
Data diddling
Data leakage
Denial of service attacks
Eavesdropping
Email threats
Email forgery (aka, spoofing )
Hacking
Phreaking
Hijacking
Identity theft
Victims can usually clear their credit, but the effort requires a significant amount of time and expense.
Identity theft was made a federal offense in 1998, but it is a growing crime industry.
One U.S. postal inspector, whose job duties involved investigation of identity thefts, was himself a victim. The thief ran up $80,000 in debt under the postal inspector’s identity before the inspector discovered the problem.
COMPUTER FRAUD AND ABUSE TECHNIQUES
Perpetrators have devised many methods to commit computer fraud and abuse. These include:
Data diddling
Data leakage
Denial of service attacks
Eavesdropping
Email threats
Email forgery (aka, spoofing )
Hacking
Phreaking
Hijacking
Identity theft
Identity thieves can steal corporate or individual identities by:
Shoulder surfing
Watching people enter telephone calling card numbers or credit card numbers or listening to communications as they provide this information to sales clerks or others.
Scavenging or dumpster diving
Searching corporate or personal records by rifling garbage cans, communal trash bins, and city dumps for documents with confidential company information.
May also look for personal information such as checks, credit card statements, bank statements, tax returns, discarded applications for pre-approved credit cards, or other records that contain social security numbers, names, addresses, phone numbers, and other data that allow them to assume an identity.
Redirecting mail
Intercepting mail and having it delivered to a location where others can access it.
Using Internet, email, and other technology in spoofing, phishing, eavesdropping, impersonating, social engineering, and data leakage schemes.
COMPUTER FRAUD AND ABUSE TECHNIQUES
Perpetrators have devised many methods to commit computer fraud and abuse. These include:
Data diddling
Data leakage
Denial of service attacks
Eavesdropping
Email threats
Email forgery (aka, spoofing )
Hacking
Phreaking
Hijacking
Identity theft
The U.S. Department of Justice suggests the following four ways to minimize the chances of being victimized by identity theft:
Do not give out corporate or personal information unless there is a good reason to trust the person to whom it is given.
Check financial information regularly for what should be there, as well as for what should not be there.
Periodically review your credit report.
Maintain careful records of banking and financial accounts.
COMPUTER FRAUD AND ABUSE TECHNIQUES
Perpetrators have devised many methods to commit computer fraud and abuse. These include:
Internet misinformation
Using the Internet to spread false or misleading information about people or companies.
May involve:
Planting inflammatory messages in online chat rooms.
Websites with misinformation.
Pretending to be someone else online and making inflammatory comments that will be attributed to that person.
A “pump-and-dump” occurs when an individual spreads misinformation, often through Internet chat rooms, to cause a run-up in the value a stock and then sells off his shares of the stock. A number of pump-and-dump cases have been prosecuted by the SEC.
COMPUTER FRAUD AND ABUSE TECHNIQUES
Perpetrators have devised many methods to commit computer fraud and abuse. These include:
Internet misinformation
Another common form of Internet misinformation is the spreading of “urban legends”—often by innocently forwarding emails.
Urban legends may often include damaging implications about company products, such as a recent email suggesting that certain lipsticks contain lead or that using plastic cookware in the microwave can cause cancer.
Before forwarding any emails with negative information about individuals, companies, or their products, it’s a good idea to check the veracity of the information first.
Emails with urban legends often attribute their “facts” to credible sources, such as the federal government, Stanford University researchers, the FBI, etc.
There are several websites that attempt to verify the truth of emails that are circulated. One such website is www.snopes.com . You can easily locate the email you received on these websites, by searching under a key term in the email, such as “lipstick.”
You are likely to find that most emails you were getting ready to forward are either false or only partially true.
COMPUTER FRAUD AND ABUSE TECHNIQUES
Perpetrators have devised many methods to commit computer fraud and abuse. These include:
Internet misinformation
Internet terrorism
Hackers use the Internet to disrupt electronic commerce and destroy company and individual communications.
Viruses and worms are two main forms of Internet terrorism.
COMPUTER FRAUD AND ABUSE TECHNIQUES
Perpetrators have devised many methods to commit computer fraud and abuse. These include:
Internet misinformation
Internet terrorism
Logic time bombs
A program that lies idle until triggered by some circumstance or a particular time.
Once triggered, it sabotages the system, destroying programs, data, or both.
Usually written by disgruntled programmers.
EXAMPLE: A programmer places a logic bomb in a payroll application that will destroy all the payroll records if the programmer is terminated.
COMPUTER FRAUD AND ABUSE TECHNIQUES
Perpetrators have devised many methods to commit computer fraud and abuse. These include:
Internet misinformation
Internet terrorism
Logic time bombs
Masquerading or impersonation
The perpetrator gains access to the system by pretending to be an authorized user.
The perpetrator must know the legitimate user’s ID and password.
Once in the system, he enjoys the same privileges as the legitimate user.
COMPUTER FRAUD AND ABUSE TECHNIQUES
Perpetrators have devised many methods to commit computer fraud and abuse. These include:
Internet misinformation
Internet terrorism
Logic time bombs
Masquerading or impersonation
Packet sniffers
Programs that capture data from information packets as they travel over the Internet or company networks.
Confidential information and access information can be gleaned from the captured data—some of which is later sold.
COMPUTER FRAUD AND ABUSE TECHNIQUES
Perpetrators have devised many methods to commit computer fraud and abuse. These include:
Internet misinformation
Internet terrorism
Logic time bombs
Masquerading or impersonation
Packet sniffers
Password cracking
An intruder penetrates a system’s defenses, steals the file of valid passwords, decrypts them, and then uses them to gain access to almost any system resources.
COMPUTER FRAUD AND ABUSE TECHNIQUES
Perpetrators have devised many methods to commit computer fraud and abuse. These include:
Internet misinformation
Internet terrorism
Logic time bombs
Masquerading or impersonation
Packet sniffers
Password cracking
Phishing
Sending out a spoofed email that appears to come from a legitimate company, such as a financial institution. EBay, PayPal, and banks are commonly spoofed.
The recipient is advised that information or a security check is needed on his account, and advised to click on a link to the company’s website to provide the information.
The link connects the individual to a website that is an imitation of the spoofed company’s actual website. These counterfeit websites appear very authentic, as do the emails.
COMPUTER FRAUD AND ABUSE TECHNIQUES
Perpetrators have devised many methods to commit computer fraud and abuse. These include:
Internet misinformation
Internet terrorism
Logic time bombs
Masquerading or impersonation
Packet sniffers
Password cracking
Phishing
One newly graduated college student recently took a job in California and deposited his first paycheck of approximately $5,000 in the bank.
That same night, he received an email from the bank, inviting him to click on the link in the email to set up online banking for his new bank account.
He followed directions and provided the requested information to set up online banking.
Two hours later, he was nervous and called the bank—only to find out that his bank account had been cleaned out and closed.
COMPUTER FRAUD AND ABUSE TECHNIQUES
Perpetrators have devised many methods to commit computer fraud and abuse. These include:
Internet misinformation
Internet terrorism
Logic time bombs
Masquerading or impersonation
Packet sniffers
Password cracking
Phishing
As a rule of thumb, it is a good idea not to click on any link provided in an email and to go directly to the website instead.
PayPal, whose email address is commonly spoofed for phishing scams, offers the following advice:
If PayPal ever sends you an email, they will include your first and last name in the salutation of the email.
If you need to enter PayPal’s website, type “https:” in the URL instead of “http:” in order to enter on the company’s secured server.
If you receive a suspicious email, get out of your browser and go back in before proceeding directly to a company website.
COMPUTER FRAUD AND ABUSE TECHNIQUES
Perpetrators have devised many methods to commit computer fraud and abuse. These include:
Internet misinformation
Internet terrorism
Logic time bombs
Masquerading or impersonation
Packet sniffers
Password cracking
Phishing
In 2004, a phishing-related scam took place in South America with respect to three large South American banks. Once an individual opened the related email, a script was downloaded on their computer. The script would alter the individual’s web browser so that if the user entered the URL of one of these three banks, the browser would redirect them to a counterfeit website for that bank. The oblivious user would provide ID and password information, and was instantly set up for a high-tech robbery of his bank account.
COMPUTER FRAUD AND ABUSE TECHNIQUES
Perpetrators have devised many methods to commit computer fraud and abuse. These include:
Internet misinformation
Internet terrorism
Logic time bombs
Masquerading or impersonation
Packet sniffers
Password cracking
Phishing
Consumer Reports suggests that if you have any questions about the legitimacy of a website, you should try entering the wrong password. A phishing website will typically accept an incorrect password—which cues you that it is a phishing scam.
COMPUTER FRAUD AND ABUSE TECHNIQUES
Example of a website produced for a phishing scam.
COMPUTER FRAUD AND ABUSE TECHNIQUES
Perpetrators have devised many methods to commit computer fraud and abuse. These include:
Internet misinformation
Internet terrorism
Logic time bombs
Masquerading or impersonation
Packet sniffers
Password cracking
Phishing
Piggybacking
Tapping into a telecommunications line and latching onto a legitimate user before that user logs into a system.
The legitimate user unknowingly carries the perpetrator into the system.
COMPUTER FRAUD AND ABUSE TECHNIQUES
Perpetrators have devised many methods to commit computer fraud and abuse. These include:
Internet misinformation
Internet terrorism
Logic time bombs
Masquerading or impersonation
Packet sniffers
Password cracking
Phishing
Piggybacking
Round-down technique
Made famous in the movie, Office Space .
The programmer instructs the computer to round interest calculations down to two decimal places and deposits the remaining fraction into the account of a programmer or an accomplice.
COMPUTER FRAUD AND ABUSE TECHNIQUES
Perpetrators have devised many methods to commit computer fraud and abuse. These include:
Internet misinformation
Internet terrorism
Logic time bombs
Masquerading or impersonation
Packet sniffers
Password cracking
Phishing
Piggybacking
Round-down technique
Salami technique
Involves the theft of tiny slices of money over a period of time.
The round-down is just a special form of a salami technique.
COMPUTER FRAUD AND ABUSE TECHNIQUES
Perpetrators have devised many methods to commit computer fraud and abuse. These include:
Social engineering
Perpetrators trick employees into giving them information they need to get into the system.
A perpetrator might call an employee and indicate he is the systems administrator and needs to get the employee’s password.
COMPUTER FRAUD AND ABUSE TECHNIQUES
Perpetrators have devised many methods to commit computer fraud and abuse. These include:
Social engineering
Software piracy
Copying software without the publisher’s permission.
In the U.S., it’s estimated that 26% of software in use is pirated.
Fines for individuals and corporations are stiff, and individuals convicted of software piracy can serve jail terms of up to 5 years.
COMPUTER FRAUD AND ABUSE TECHNIQUES
Perpetrators have devised many methods to commit computer fraud and abuse. These include:
Social engineering
Software piracy
Spamming
Emailing an unsolicited message to multitudes of people, often in an attempt to sell a product.
Many times the product offers are fraudulent.
COMPUTER FRAUD AND ABUSE TECHNIQUES
Perpetrators have devised many methods to commit computer fraud and abuse. These include:
Social engineering
Software piracy
Spamming
Spammers use creative means to find valid email addresses:
Scanning the Internet for addresses posted online.
Hacking into company databases and stealing mailing lists.
Staging dictionary (aka direct harvesting ) attacks .
These attacks use special software to guess addresses at a particular company and send blank emails.
Messages not returned are usually valid.
These attacks are very burdensome to corporate email systems.
COMPUTER FRAUD AND ABUSE TECHNIQUES
Perpetrators have devised many methods to commit computer fraud and abuse. These include:
Social engineering
Software piracy
Spamming
Companies may use filtering software to detect dictionary attacks, search mail for competitive leaks, and block inappropriate attachments, such as pornography and illegal MP3 files.
Filtering is not always viable. The director of internal audit at a major healthcare company changes email addresses frequently because of the volume of spam email in his inbox. When asked why his company did not filter the spam, he replied, “Because we’re a healthcare company, we cannot filter out any references to body parts or prescription medications.”
There is increasing public clamor for laws to clamp down on spamming. In December 2004, a federal judge awarded over $1 billion to a small Midwestern Internet service provider in an action against three spammers.
COMPUTER FRAUD AND ABUSE TECHNIQUES
Perpetrators have devised many methods to commit computer fraud and abuse. These include:
Social engineering
Software piracy
Spamming
Spyware
Software that monitors computing habits, such as web-surfing habits, and sends the data it gathers to someone else, typically without the user’s permission.
One type, called adware (for advertising-supported software) does two things:
Causes banner ads to pop up on your monitor as you surf the net.
Collects information about your Web-surfing and spending habits and forwards it to a company gathering the data—often an advertising or large media organization.
COMPUTER FRAUD AND ABUSE TECHNIQUES
Perpetrators have devised many methods to commit computer fraud and abuse. These include:
Social engineering
Software piracy
Spamming
Spyware
Usually comes bundled with freeware and shareware downloaded from the Internet.
May be disclosed in the licensing agreement, but users are unlikely to read it.
Reputable adware companies claim they don’t collect sensitive or identifying data.
But there is no way for users to control or limit the activity.
It is not illegal, but many find it objectionable.
Software has been developed to detect and eliminate spyware, but it may also impair the downloaded software.
Some is intentionally difficult to uninstall.
COMPUTER FRAUD AND ABUSE TECHNIQUES
Perpetrators have devised many methods to commit computer fraud and abuse. These include:
Social engineering
Software piracy
Spamming
Spyware
Keystroke loggers
A keystroke logger records a user’s keystrokes and emails them to or saves them for the party that planted the logger. These are sometimes used by:
Parents to monitor their children’s computer usage.
Businesses to monitor employee activity.
Fraudsters to capture passwords, credit card numbers, etc.
A keystroke logger can be a hardware device attached to a computer or can be downloaded on an individual’s computer in the same way that any Trojan horse might be downloaded.
COMPUTER FRAUD AND ABUSE TECHNIQUES
Perpetrators have devised many methods to commit computer fraud and abuse. These include:
Social engineering
Software piracy
Spamming
Spyware
Keystroke loggers
Spyware and keystroke loggers are very problematic for companies with employees who telecommute or contact the company’s computer from remote locations.
Spyware on those computers makes the company’s systems vulnerable.
Individuals are also exposed when they use wireless networks, such as those that may be available in coffee shops.
COMPUTER FRAUD AND ABUSE TECHNIQUES
Perpetrators have devised many methods to commit computer fraud and abuse. These include:
Social engineering
Software piracy
Spamming
Spyware
Keystroke loggers
Superzapping
Unauthorized use of special system programs to bypass regular system controls and perform illegal acts.
The name is derived from an IBM software utility called Superzap that was used to restored crashed systems.
COMPUTER FRAUD AND ABUSE TECHNIQUES
Perpetrators have devised many methods to commit computer fraud and abuse. These include:
Social engineering
Software piracy
Spamming
Spyware
Keystroke loggers
Superzapping
Trap doors
Also called back doors .
Programmers create trap doors to modify programs.
The trap door is a way into the system that bypasses normal controls.
The trap door should be removed before the program is implemented.
If it is not, the programmer or others may later gain unauthorized access to the system.
COMPUTER FRAUD AND ABUSE TECHNIQUES
Perpetrators have devised many methods to commit computer fraud and abuse. These include:
Social engineering
Software piracy
Spamming
Spyware
Keystroke loggers
Superzapping
Trap doors
Trojan horse
A set of unauthorized computer instructions planted in an authorized and otherwise properly functioning program.
Allows the creator to control the victim’s computer remotely.
The code does not try to replicate itself but performs an illegal act at some specific time or when some condition arises.
Programs that launch denial of service attacks are often Trojan horses.
COMPUTER FRAUD AND ABUSE TECHNIQUES
Perpetrators have devised many methods to commit computer fraud and abuse. These include:
Social engineering
Software piracy
Spamming
Spyware
Keystroke loggers
Superzapping
Trap doors
Trojan horse
War dialing
Hackers search for an idle modem by programming their computers to dial thousands of phone lines.
Hackers enter through the idle modem and gain access to the connected network.
COMPUTER FRAUD AND ABUSE TECHNIQUES
Perpetrators have devised many methods to commit computer fraud and abuse. These include:
Social engineering
Software piracy
Spamming
Spyware
Keystroke loggers
Superzapping
Trap doors
Trojan horse
War dialing
War driving
Driving around in cars looking for unprotected home or corporate wireless networks.
If the hackers mark the sidewalk of the susceptible wireless network, the practice is referred to as warchalking .
COMPUTER FRAUD AND ABUSE TECHNIQUES
Perpetrators have devised many methods to commit computer fraud and abuse. These include:
Virus
Many viruses have two phases:
First, when some predefined event occurs, the virus replicates itself and spreads to other systems or files.
Another event triggers the attack phase in which the virus carries out its mission.
A virus may lay dormant or propagate itself without causing damage for an extended period.
COMPUTER FRAUD AND ABUSE TECHNIQUES
Perpetrators have devised many methods to commit computer fraud and abuse. These include:
Virus
Damage may take many forms:
Send email with the victim’s name as the alleged source.
Destroy or alter data or programs.
Take control of the computer.
Destroy or alter file allocation tables.
Delete or rename files or directories.
Reformat the hard drive.
Change file content.
Prevent users from booting.
Intercept and change transmissions.
Print disruptive images or messages on the screen.
Change screen appearance.
As viruses spread, they take up much space, clog communications, and hinder system performance.
COMPUTER FRAUD AND ABUSE TECHNIQUES
Perpetrators have devised many methods to commit computer fraud and abuse. These include:
Virus
Virus symptoms:
Computer will not start or execute
Performs unexpected read or write operations
Unable to save files
Long time to load programs
Abnormally large file sizes
Slow systems operation
Unusual screen activity
Error messages
COMPUTER FRAUD AND ABUSE TECHNIQUES
Perpetrators have devised many methods to commit computer fraud and abuse. These include:
Virus
Viruses are contagious and easily spread from one system to another.
They are usually spread by:
Opening an infected email attachment or file (most common); or
Running an infected program.
Some viruses can mutate, which makes them more difficult to detect and destroy.
The emails often appear to come from sources like Microsoft and seem very convincing.
COMPUTER FRAUD AND ABUSE TECHNIQUES
Perpetrators have devised many methods to commit computer fraud and abuse. These include:
Virus
Virus protections include:
Install reliable virus software that scans for, identifies, and destroys viruses.
Keep the antivus program up to date.
Scan incoming email at the server level, rather than when it hits the desktops.
Certify all software as virus-free before loading it.
Software from unknown sources may be virus bait, especially if it seems too good to be true.
Deal with trusted software retailers.
Use electronic techniques to make tampering evident.
Check new software on an isolated machine.
Have two backups of all files.
Do not put diskettes or CDs in strange machines, or let others put unscanned disks in your machine.
COMPUTER FRAUD AND ABUSE TECHNIQUES
Perpetrators have devised many methods to commit computer fraud and abuse. These include:
Virus
Viruses attack computers, but any device that is part of the communications network is vulnerable, including:
Cell phones
Smart phones
PDAs
COMPUTER FRAUD AND ABUSE TECHNIQUES
Perpetrators have devised many methods to commit computer fraud and abuse. These include:
Virus
Worms
A worm is similar to a virus except for:
A worm is a stand-alone program, while a virus is only a segment of code hidden in a host program or executable file.
A worm will replicate itself automatically, while a virus requires a human to do something like open a file.
Worms often reproduce by mailing themselves to the recipient’s mailing list.
They are not confined to PCs and have infected cell phones in Japan.
A worm typically has a short but very destructive life.
It takes little technical knowledge to create worms or viruses; several websites provide instructions.
Most exploit known software vulnerabilities that can be corrected with a software patch, making it important to install all patches as soon as they are available.
COMPUTER FRAUD AND ABUSE TECHNIQUES
Perpetrators have devised many methods to commit computer fraud and abuse. These include:
Virus
Worms
The low-tech, do-it-yourself attack
You receive an email from a friend, apologizing profusely that he/she has previously sent you an email that was infected with a virus.
The friend’s email gives you instructions to look for and remove the offending virus.
You delete the file from your hard drive. The only problem is that the file you just deleted was part of your operating system.
Your friend was well-intended and has done the same thing to his/her computer.
REMEDY: Before even considering following instructions of this sort, check the list of hoaxes that are available on any virus protection website, such as:
www.norton.com
www.mcafee.com
INTRODUCTION
In this chapter we’ll discuss:
The fraud process
Why fraud occurs
Approaches to computer fraud
Specific techniques used to commit computer fraud
Ways companies can deter and detect computer fraud
PREVENTING AND DETECTING COMPUTER FRAUD
Organizations must take every precaution to protect their information systems.
Certain measures can significantly decrease the potential for fraud and any resulting losses.
These measures include:
Make fraud less likely to occur
Increase the difficulty of committing fraud
Improve detection methods
Reduce fraud losses
PREVENTING AND DETECTING COMPUTER FRAUD
Organizations must take every precaution to protect their information systems.
Certain measures can significantly decrease the potential for fraud and any resulting losses.
These measures include:
Make fraud less likely to occur
Increase the difficulty of committing fraud
Improve detection methods
Reduce fraud losses
PREVENTING AND DETECTING COMPUTER FRAUD
Make fraud less likely to occur
Create a culture that stresses integrity and commitment to ethical values and competence.
Adopt an organizational structure, management philosophy, operating style, and appetite for risk that minimizes the likelihood of fraud.
Require oversight from an active, involved, and independent audit committee.
Assign authority and responsibility for business objectives to specific departments and individuals, encourage initiative in solving problems, and hold them accountable for achieving those objectives.
PREVENTING AND DETECTING COMPUTER FRAUD
Identify the events that lead to increased fraud risk, and take steps to prevent, avoid, share, or accept that risk.
Develop a comprehensive set of security policies to guide the design and implementation of specific control procedures, and communicate them effectively to company employees.
Implement human resource policies for hiring, compensating, evaluating, counseling, promoting, and discharging employees that send messages about the required level of ethical behavior and integrity.
Effectively supervise employees, including monitoring their performance and correcting their errors.
PREVENTING AND DETECTING COMPUTER FRAUD
Train employees in integrity and ethical considerations, as well as security and fraud prevention measures.
Require annual employee vacations, periodically rotate duties of key employees, and require signed confidentiality agreements.
Implement formal and rigorous project development and acquisition controls, as well as change management controls.
Increase the penalty for committing fraud by prosecuting fraud perpetrators more vigorously.
PREVENTING AND DETECTING COMPUTER FRAUD
Organizations must take every precaution to protect their information systems.
Certain measures can significantly decrease the potential for fraud and any resulting losses.
These measures include:
Make fraud less likely to occur
Increase the difficulty of committing fraud
Improve detection methods
Reduce fraud losses
PREVENTING AND DETECTING COMPUTER FRAUD
Increase the difficulty of committing fraud
Develop a strong system of internal controls
Segregate the accounting functions of:
Authorization
Recording
Custody
Implement a program segregation of duties between systems functions
Restrict physical and remote access to system resources to authorized personnel
PREVENTING AND DETECTING COMPUTER FRAUD
Require transactions and activities to be authorized by appropriate supervisory personnel. Have the system authenticate the person and their right to perform the transaction before allowing the transaction to take place.
Use properly designed documents and records to capture and process transactions.
Safeguard all assets, records, and data.
Require independent checks on performance, such as reconciliation of two independent sets of records, where possible and appropriate.
PREVENTING AND DETECTING COMPUTER FRAUD
Implement computer-based controls over data input, computer processing, data storage, data transmission, and information output.
Encrypt stored and transmitted data and programs to protect them from unauthorized access and use.
Fix known software vulnerabilities by installing the latest updates to operating systems, security, and applications programs.
PREVENTING AND DETECTING COMPUTER FRAUD
Organizations must take every precaution to protect their information systems.
Certain measures can significantly decrease the potential for fraud and any resulting losses.
These measures include:
Make fraud less likely to occur
Increase the difficulty of committing fraud
Improve detection methods
Reduce fraud losses
PREVENTING AND DETECTING COMPUTER FRAUD
Improve detection methods.
Create an audit trail so individual transactions can be traced through the system to the financial statements and vice versa.
Conduct periodic external and internal audits, as well as special network security audits.
Install fraud detection software.
Implement a fraud hotline.
PREVENTING AND DETECTING COMPUTER FRAUD
Employ a computer security officer, as well as computer consultants and forensic specialists as needed.
Monitor system activities, including computer and network security efforts, usage and error logs, and all malicious actions.
Use intrusion detection systems to help automate the monitoring process.
PREVENTING AND DETECTING COMPUTER FRAUD
Organizations must take every precaution to protect their information systems.
Certain measures can significantly decrease the potential for fraud and any resulting losses.
These measures include:
Make fraud less likely to occur
Increase the difficulty of committing fraud
Improve detection methods
Reduce fraud losses
PREVENTING AND DETECTING COMPUTER FRAUD
Reduce Fraud Losses
Maintain adequate insurance.
Develop comprehensive fraud contingency, disaster recovery, and business continuity plans.
Store backup copies of program and data files in a secure, off-site location.
Use software to monitor system activity and recover from fraud.
SUMMARY
In this chapter, you’ve learned what fraud is, who commits fraud, and how it’s perpetrated.
You’ve learned about the many variations of computer fraud, and you’ve learned about techniques to reduce an organization’s vulnerability to these types of fraud.

Ais Romney 2006 Slides 04 Relational Databases

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Ais Romney 2006 Slides 04 Relational Databases - Presentation Transcript

HAPTER 4 Relational Databases
INTRODUCTION
Questions to be addressed in this chapter:
How are databases different than file-based legacy systems?
Why are databases important and what is their advantage?
What is the difference between logical and physical views of a database?
What are the fundamental concepts of database systems such as DBMS, schemas, the data dictionary, and DBMS languages?
What is a relational database, and how does it organize data?
How are tables structured to properly store data in a relational database?
INTRODUCTION
Relational databases underlie most modern integrated AISs.
They are the most popular type of database used for transaction processing.
In this chapter, we’ll define the concept of a database.
FILE VS. DATABASES
Let’s examine some basic principles about how data are stored in computer systems.
An entity is anything about which the organization wishes to store data. At your college or university, one entity would be the student.
04/20/85 555-5555 Artie Moore 123-45-6789 11/24/86 444-4444 Ned Sanders 111-11-1111 10/11/84 333-3333 Alice Simpson 333-33-3333 Birth Date Phone Number First Name Last Name Student ID STUDENTS
FILE VS. DATABASES
Information about the attributes of an entity (e.g., the student’s ID number and birth date) are stored in fields .
04/20/85 555-5555 Artie Moore 123-45-6789 11/24/86 444-4444 Ned Sanders 111-11-1111 10/11/84 333-3333 Alice Simpson 333-33-3333 Birth Date Phone Number First Name Last Name Student ID STUDENTS
FILE VS. DATABASES
All the fields containing data about one entity (e.g., one student) form a record .
The example below shows the record for Artie Moore.
04/20/85 555-5555 Artie Moore 123-45-6789 11/24/86 444-4444 Ned Sanders 111-11-1111 10/11/84 333-3333 Alice Simpson 333-33-3333 Birth Date Phone Number First Name Last Name Student ID STUDENTS
FILE VS. DATABASES
A set of all related records forms a file (e.g., the student file).
If this university only had three students and five fields for each student, then the entire file would be depicted below.
04/20/85 555-5555 Artie Moore 123-45-6789 11/24/86 444-4444 Ned Sanders 111-11-1111 10/11/84 333-3333 Alice Simpson 333-33-3333 Birth Date Phone Number First Name Last Name Student ID STUDENTS
FILE VS. DATABASES
A set of interrelated, centrally coordinated files forms a database .
Student File Class File Advisor File
FILE VS. DATABASES
Database systems were developed to address the problems associated with the proliferation of master files.
For years, each time a new information need arose, companies created new files and programs.
The result: a significant increase in the number of master files.
FILE VS. DATABASES
This proliferation of master files created problems:
Often the same information was stored in multiple master files.
Made it more difficult to effectively integrate data and obtain an organization-wide view of the data.
Also, the same information may not have been consistent between files.
If a student changed his phone number, it may have been updated in one master file but not another.
Master File 1 Fact A Fact B Fact C Master File 2 Fact A Fact D Fact F Master File 1 Fact A Fact B Fact F Enrollment Program Fin. Aid Program Grades Program
FILE VS. DATABASES
A database is a set of inter-related, centrally coordinated files.
Database Fact A Fact B Fact C Fact D Fact E Fact F Enrollment Program Fin. Aid Program Grades Program Database Management System
FILE VS. DATABASES
The database approach treats data as an organizational resource that should be used by and managed for the entire organization, not just a particular department.
A database management system (DBMS) serves as the interface between the database and the various application programs.
Database Fact A Fact B Fact C Fact D Fact E Fact F Enrollment Program Fin. Aid Program Grades Program Database Management System
FILE VS. DATABASES
The combination of the database, the DBMS, and the application programs that access the database is referred to as the database system .
Database Fact A Fact B Fact C Fact D Fact E Fact F Enrollment Program Fin. Aid Program Grades Program Database Management System
FILE VS. DATABASES
The person responsible for the database is the database administrator .
As technology improves, many large companies are developing very large databases called data warehouses.
Database Fact A Fact B Fact C Fact D Fact E Fact F Enrollment Program Fin. Aid Program Grades Program Database Management System
IMPORTANCE AND ADVANTAGES OF DATABASE SYSTEMS
Database technology is everywhere.
Most new AISs implement a database approach.
Virtually all mainframe computer sites use database technology.
Use of databases with PCs is growing also.
IMPORTANCE AND ADVANTAGES OF DATABASE SYSTEMS
As accountants, you are likely to audit or work for companies that use database technology to store, process, and report accounting transactions.
Many accountants work directly with databases and will enter, process, and query databases.
Some will develop and evaluate internal controls necessary to ensure database integrity.
Others will be involved in the design and management of databases.
IMPORTANCE AND ADVANTAGES OF DATABASE SYSTEMS
Database technology provides the following benefits to organizations:
Data integration
Achieved by combining master files into larger pools of data accessible by many programs.
IMPORTANCE AND ADVANTAGES OF DATABASE SYSTEMS
Database technology provides the following benefits to organizations:
Data integration
Data sharing
It’s easier to share data that’s integrated.
IMPORTANCE AND ADVANTAGES OF DATABASE SYSTEMS
Database technology provides the following benefits to organizations:
Data integration
Data sharing
Reporting flexibility
Reports can be revised easily and generated as needed.
The database can easily be browsed to research problems or obtain detailed information.
IMPORTANCE AND ADVANTAGES OF DATABASE SYSTEMS
Database technology provides the following benefits to organizations:
Data integration
Data sharing
Reporting flexibility
Minimal data redundancy and inconsistencies
Because data items are usually stored only once.
IMPORTANCE AND ADVANTAGES OF DATABASE SYSTEMS
Database technology provides the following benefits to organizations:
Data integration
Data sharing
Reporting flexibility
Minimal data redundancy and inconsistencies
Data independence
Data items are independent of the programs that use them.
Consequently, a data item can be changed without changing the program and vice versa.
Makes programming easier and simplifies data management.
IMPORTANCE AND ADVANTAGES OF DATABASE SYSTEMS
Database technology provides the following benefits to organizations:
Data integration
Data sharing
Reporting flexibility
Minimal data redundancy and inconsistencies
Data independence
Central management of data
Data management is more efficient because the database administrator is responsible for coordinating, controlling, and managing data.
IMPORTANCE AND ADVANTAGES OF DATABASE SYSTEMS
Database technology provides the following benefits to organizations:
Data integration
Data sharing
Reporting flexibility
Minimal data redundancy and inconsistencies
Data independence
Central management of data
Cross-functional analysis
Relationships can be explicitly defined and used in the preparation of management reports.
EXAMPLE: Relationship between selling costs and promotional campaigns.
DATABASE SYSTEMS
Logical and Physical Views of Data
In file-oriented systems, programmers must know the physical location and layout of records used by a program.
They must reference the location, length, and format of every field they utilize.
When data is used from several files, this process becomes more complex.
DATABASE SYSTEMS
Database systems overcome this problem by separating the storage and use of data elements.
Two separate views of the data are provided:
Logical view
How the user or programmer conceptually organizes and understands the data.
DATABASE SYSTEMS
Database systems overcome this problem by separating the storage and use of data elements.
Two separate views of the data are provided:
Logical view
Physical view
How and where the data are physically arranged and stored.
DATABASE SYSTEMS
Database systems overcome this problem by separating the storage and use of data elements.
Two separate views of the data are provided:
Logical view
Physical view
Separating these views facilitates application development, because programmers can focus on coding the logic and not be concerned with storage details.
Database Enrollment by Class Logical View—User A Logical View—User B DBMS Operating System The DBMS translates users’ logical views into instructions as to which data should be retrieved from the database.
Database Enrollment by Class Logical View—User A Logical View—User B DBMS Operating System The operating system translates DBMS requests into instructions to physically retrieve data from various disks.
DATABASE SYSTEMS
The DBMS handles the link between the physical and logical views of the data.
Allows the user to access, query, and update data without reference to how or where it is physically stored.
The user only needs to define the logical data requirements.
DATABASE SYSTEMS
Separating the logical and physical views of data also means users can change their conceptualizations of the data relationships without making changes in the physical storage.
The database administrator can also change the physical storage of the data without affecting users or application programs.
DATABASE SYSTEMS
Schemas
A schema describes the logical structure of a database.
There are three levels of schema.
Conceptual level
The organization-wide view of the entire database—i.e., the big picture.
Lists all data elements and the relationships between them.
Subschema--User A Smith . . . A Jones . . . B Arnold . . .D Subschema--User B Subschema--User C Enroll Cash Receipt Classes Student Mapping external-level views to conceptual-level schema Mapping conceptual-level items to internal-level descriptions
DATABASE SYSTEMS
Schemas
A schema describes the logical structure of a database.
There are three levels of schema.
Conceptual level
External level
A set of individual user views of portions of the database, i.e., how each user sees the portion of the system with which he interacts.
These individual views are referred to as subschema .
Subschema--User A Smith . . . A Jones . . . B Arnold . . .D Subschema--User B Subschema--User C Enroll Cash Receipt Classes Student Mapping external-level views to conceptual-level schema Mapping conceptual-level items to internal-level descriptions
DATABASE SYSTEMS
Schemas
A schema describes the logical structure of a database.
There are three levels of schema.
Conceptual level
External level
Internal level
A low-level view of the database.
It describes how the data are actually stored and accessed including:
Record layouts
Definitions
Addresses
Indexes
Subschema--User A Smith . . . A Jones . . . B Arnold . . .D Subschema--User B Subschema--User C Enroll Cash Receipt Classes Student Mapping external-level views to conceptual-level schema Mapping conceptual-level items to internal-level descriptions
Subschema--User A Smith . . . A Jones . . . B Arnold . . .D Subschema--User B Subschema--User C Enroll Cash Receipt Classes Student Mapping external-level views to conceptual-level schema Mapping conceptual-level items to internal-level descriptions The bidirectional arrows represent mappings between the schema.
DATABASE SYSTEMS
The DBMS uses the mappings to translate a request by a user or program for data (expressed in logical names and relationships) into the indexes and addresses needed to physically access the data.
DATABASE SYSTEMS
Accountants are frequently involved in developing conceptual- and external-level schema.
An employee’s access to data should be limited to the subschema of data that is relevant to the performance of his job.
DATABASE SYSTEMS
The Data Dictionary
A key component of a DBMS is the data dictionary.
Contains information about the structure of the database.
For each data element, there is a corresponding record in the data dictionary describing that element.
DATABASE SYSTEMS
Information provided for each element includes:
A description or explanation of the element.
The records in which it is contained.
Its source.
The length and type of the field in which it is stored.
The programs in which it is used.
The outputs in which it is contained.
The authorized users of the element.
Other names for the element.
DATABASE SYSTEMS
Accountants should participate in the development of the data dictionary because they have a good understanding of the data elements in a business organization, as well as where those elements originate and how they are used.
DATABASE SYSTEMS
The DBMS usually maintains the data dictionary.
It is often one of the first applications of a newly implemented database system.
Inputs to the dictionary include:
Records of new or deleted data elements.
Changes in names, descriptions, or uses of existing elements.
Outputs include:
Reports that are useful to programmers, database designers, and IS users in:
Designing and implementing the system.
Documenting the system.
Creating an audit trail.
DATABASE SYSTEMS
DBMS Languages
Every DBMS must provide a means of performing the three basic functions of:
Creating a database
Changing a database
Querying a database
DATABASE SYSTEMS
DBMS Languages
Every DBMS must provide a means of performing the three basic functions of:
Creating a database
Changing a database
Querying a database
DATABASE SYSTEMS
Creating a database:
The set of commands used to create the database is known as data definition language (DDL) . DDL is used to:
Build the data dictionary
Initialize or create the database
Describe the logical views for each individual user or programmer
Specify any limitations or constraints on security imposed on database records or fields
DATABASE SYSTEMS
DBMS Languages
Every DBMS must provide a means of performing the three basic functions of:
Creating a database
Changing a database
Querying a database
DATABASE SYSTEMS
Changing a database
The set of commands used to change the database is known as data manipulation language (DML) . DML is used for maintaining the data including:
Updating data
Inserting data
Deleting portions of the database
DATABASE SYSTEMS
DBMS Languages
Every DBMS must provide a means of performing the three basic functions of:
Creating a database
Changing a database
Querying a database
DATABASE SYSTEMS
Querying a database:
The set of commands used to query the database is known as data query language (DQL) . DQL is used to interrogate the database, including:
Retrieving records
Sorting records
Ordering records
Presenting subsets of the database
The DQL usually contains easy-to-use, powerful commands that enable users to satisfy their own information needs.
DATABASE SYSTEMS
Report Writer
Many DBMS packages also include a report writer , a language that simplifies the creation of reports.
Users typically specify:
What elements they want printed
How the report should be formatted
The report writer then:
Searches the database
Extracts specified data
Prints them out according to specified format
DATABASE SYSTEMS
Users typically have access to both DQL and report writer.
Access to DQL and DML are typically restricted to employees with administrative and programming responsibilities.
RELATIONAL DATABASES
A DBMS is characterized by the type of logical data model on which it is based.
A data model is an abstract representation of the contents of a database.
Most new DBMSs are called relational databases because they use the relational model developed by E.F. Codd in 1970.
RELATIONAL DATABASES
The relational data model represents everything in the database as being stored in the forms of tables (aka, relations ).
Relation
RELATIONAL DATABASES
This model only describes how the data appear in the conceptual- and external-level schemas.
The data are physically stored according to the description in the internal-level schema.
Each row is called a tuple, which rhymes with “couple.”
Each row contains data about a specific occurrence of the type of entity in the table.
Each column in a table contains information about a specific attribute of the entity.
A primary key is the attribute or combination of attributes that uniquely identifies a specific row in a table.
In some tables, two or more attributes may be joined to form the primary key.
A foreign key is an attribute in one table that is a primary key in another table. 203 J.D. Radowski 1506 202 Xi Zhang 1503 316 Amy Melton 1419 420 Glen Howard 1418 Office No. First Name Last Name Advisor No. ADVISORS 1503 555-5555 Artie Moore 123-45-6789 1418 444-4444 Ned Sanders 111-11-1111 1418 333-3333 Alice Simpson 333-33-3333 Advisor No. Phone No. First Name Last Name Student ID STUDENTS
Foreign keys are used to link tables together. 203 J.D. Radowski 1506 202 Xi Zhang 1503 316 Amy Melton 1419 420 Glen Howard 1418 Office No. First Name Last Name Advisor No. ADVISORS 1503 555-5555 Artie Moore 123-45-6789 1418 444-4444 Ned Sanders 111-11-1111 1418 333-3333 Alice Simpson 333-33-3333 Advisor No. Phone No. First Name Last Name Student ID STUDENTS
Other non-key attributes in each table store important information about the entity. 203 J.D. Radowski 1506 202 Xi Zhang 1503 316 Amy Melton 1419 420 Glen Howard 1418 Office No. First Name Last Name Advisor No. ADVISORS 1503 555-5555 Artie Moore 123-45-6789 1418 444-4444 Ned Sanders 111-11-1111 1418 333-3333 Alice Simpson 333-33-3333 Advisor No. Phone No. First Name Last Name Student ID STUDENTS
RELATIONAL DATABASES
Alternatives for Storing Data
One possible alternate approach would be to store all data in one uniform table.
For example, instead of separate tables for students and classes, we could store all data in one table and have a separate line for each student x class combination.
Using the suggested approach, a student taking three classes would need three rows in the table.
In the above, simplified example, a number of problems arise.
11:00 AM Th 3 FIN-3213 555-5555 Artie Moore 123-45-6789 10:00 AM T 2 ACCT-3433 555-5555 Artie Moore 123-45-6789 9:00 AM F 7 ANSI-1422 444-4444 Ned Sanders 111-11-1111 8:00 AM W 5 MGMT-3021 444-4444 Ned Sanders 111-11-1111 10:00 AM T 2 ACCT-3433 444-4444 Ned Sanders 111-11-1111 12:00 PM TH 11 MGMT-3021 333-3333 Alice Simpson 333-33-3333 11:00 AM Th 3 FIN-3213 333-3333 Alice Simpson 333-33-3333 9:00 AM M 1 ACCT-3603 333-3333 Alice Simpson 333-33-3333 Time Day Section Course No. Phone No. First Name Last Name Student ID
Suppose Alice Simpson changes her phone number. You need to make the change in three places. If you fail to change it in all three places or change it incorrectly in one place, then the records for Alice will be inconsistent.
This problem is referred to as an update anomaly .
11:00 AM Th 3 FIN-3213 555-5555 Artie Moore 123-45-6789 10:00 AM T 2 ACCT-3433 555-5555 Artie Moore 123-45-6789 9:00 AM F 7 ANSI-1422 444-4444 Ned Sanders 111-11-1111 8:00 AM W 5 MGMT-3021 444-4444 Ned Sanders 111-11-1111 10:00 AM T 2 ACCT-3433 444-4444 Ned Sanders 111-11-1111 12:00 PM TH 11 MGMT-3021 333-3333 Alice Simpson 333-33-3333 11:00 AM Th 3 FIN-3213 333-3333 Alice Simpson 333-33-3333 9:00 AM M 1 ACCT-3603 333-3333 Alice Simpson 333-33-3333 Time Day Sect. Course No. Phone No. First Name Last Name Student ID
What happens if you have a new student to add, but he hasn’t signed up for any courses yet?
Or what if there is a new class to add, but there are no students enrolled in it yet? In either case, the record will be partially blank.
This problem is referred to as an insert anomaly .
11:00 AM Th 3 FIN-3213 555-5555 Artie Moore 123-45-6789 10:00 AM T 2 ACCT-3433 555-5555 Artie Moore 123-45-6789 9:00 AM F 7 ANSI-1422 444-4444 Ned Sanders 111-11-1111 8:00 AM W 5 MGMT-3021 444-4444 Ned Sanders 111-11-1111 10:00 AM T 2 ACCT-3433 444-4444 Ned Sanders 111-11-1111 12:00 PM TH 11 MGMT-3021 333-3333 Alice Simpson 333-33-3333 11:00 AM Th 3 FIN-3213 333-3333 Alice Simpson 333-33-3333 9:00 AM M 1 ACCT-3603 333-3333 Alice Simpson 333-33-3333 Time Day Sect. Course No. Phone No. First Name Last Name Student ID
If Ned withdraws from all his classes and you eliminate all three of his rows from the table, then you will no longer have a record of Ned. If Ned is planning to take classes next semester, then you probably didn’t really want to delete all records of him.
This problem is referred to as a delete anomaly .
11:00 AM Th 3 FIN-3213 555-5555 Artie Moore 123-45-6789 10:00 AM T 2 ACCT-3433 555-5555 Artie Moore 123-45-6789 9:00 AM F 7 ANSI-1422 444-4444 Ned Sanders 111-11-1111 8:00 AM W 5 MGMT-3021 444-4444 Ned Sanders 111-11-1111 10:00 AM T 2 ACCT-3433 444-4444 Ned Sanders 111-11-1111 12:00 PM TH 11 MGMT-3021 333-3333 Alice Simpson 333-33-3333 11:00 AM Th 3 FIN-3213 333-3333 Alice Simpson 333-33-3333 9:00 AM M 1 ACCT-3603 333-3333 Alice Simpson 333-33-3333 Time Day Sect. Course No. Phone No. First Name Last Name Student ID
RELATIONAL DATABASES
Alternatives for Storing Data
Another possible approach would be to store each student in one row of the table and create multiple columns to accommodate each class that he is taking.
This approach is also fraught with problems:
How many classes should you allow for in building the table?
The above table is quite simplified. In reality, you might need to allow for 20 or more classes (assuming a student could take many 1-hour classes). Also, more information than just the course number would be stored for each class. There would be a great deal of wasted space for all the students taking fewer than the maximum possible number of classes.
Also, if you wanted a list of every student taking MGMT-3021, notice that you would have to search multiple attributes.
FIN-3213 ACCT-3433 555-5555 Artie Moore 123-45-6789 ANSI-1422 MGMT-3021 ACCT-3433 444-4444 Ned Sanders 111-11-1111 MGMT-3021 FIN-3213 ACCT-3603 333-3333 Alice Simpson 333-33-3333 Class 4 Class 3 Class 2 Class 1 Phone No. First Name Last Name Student ID0
The solution to the preceding problems is to use a set of tables in a relational database.
Each entity is stored in a separate table, and separate tables or foreign keys can be used to link the entities together.
RELATIONAL DATABASES
Basic Requirements of a Relational Database
Every column in a row must be single valued.
In other words, every cell can have one and only one value.
In the student table, you couldn’t have an attribute named “Phone Number” if a student could have multiple phone numbers.
There might be an attribute named “local phone number” and an attribute named “permanent phone number.”
You could not have an attribute named “Class” in the student table, because a student could take multiple classes.
RELATIONAL DATABASES
Basic Requirements of a Relational Database
The primary key cannot be null.
The primary key uniquely identifies a specific row in the table, so it cannot be null, and it must be unique for every record.
This rule is referred to as the entity integrity rule .
Note that within each table, there are no duplicate primary keys and no null primary keys.
Consistent with the entity integrity rule.
RELATIONAL DATABASES
Basic Requirements of a Relational Database
A foreign key must either be null or correspond to the value of a primary key in another table.
This rule is referred to as the referential integrity rule .
The rule is necessary because foreign keys are used to link rows in one table to rows in another table.
Advisor No. is a foreign key in the STUDENTS table. Every incident of Advisor No. in the STUDENTS table either matches an instance of the primary key in the ADVISORS table or is null. 203 J.D. Radowski 1506 202 Xi Zhang 1503 316 Amy Melton 1419 420 Glen Howard 1418 Office No. First Name Last Name Advisor No. ADVISORS 1503 555-5555 Artie Moore 123-45-6789 1418 444-4444 Ned Sanders 111-11-1111 1418 333-3333 Alice Simpson 333-33-3333 Advisor No. Phone No. First Name Last Name Student ID STUDENTS
RELATIONAL DATABASES
Basic Requirements of a Relational Database
All non-key attributes in a table should describe a characteristic of the object identified by the primary key.
Could nationality be a non-key attribute in the student table?
Could advisor’s nationality be a non-key attribute in the student table?
RELATIONAL DATABASES
The preceding four constraints produce a well-structured (normalized) database in which:
Data are consistent.
Redundancy is minimized and controlled.
In a normalized database, attributes appear multiple times only when they function as foreign keys.
The referential integrity rule ensures there will be no update anomaly problem with foreign keys.
RELATIONAL DATABASES
An important feature is that data about various things of interest (entities) are stored in separate tables.
Makes it easier to add new data to the system.
You add a new student by adding a row to the student table.
You add a new course by adding a row to the course table.
Means you can add a student even if he hasn’t signed up for any courses.
And you can add a class even if no students are yet enrolled in it.
Makes it easy to avoid the insert anomaly.
Space is also used more efficiently than in the other schemes. There should be no blank rows or attributes.
Add a student here.
Leaves no blank spaces.
Add a course here.
Leaves no blank spaces.
When a particular student enrolls for a particular course, add that info here.
RELATIONAL DATABASES
Deletion of a class for a student would cause the elimination of one record in the student x class table.
The student still exists in the student table.
The class still exists in the class table.
Avoids the delete anomaly.
Ned still exists in the student table.
Even if Ned was the only student in the class, ACCT-3603 still exists in the course table.
If Ned Sanders drops ACCT-3603, remove Ned’s class from this table.
RELATIONAL DATABASES
There are two basic ways to design well-structured relational databases.
Normalization
Semantic data modeling
RELATIONAL DATABASES
There are two basic ways to design well-structured relational databases.
Normalization
Semantic data modeling
RELATIONAL DATABASES
Normalization
Starts with the assumption that everything is initially stored in one large table.
A set of rules is followed to decompose that initial table into a set of normalized tables.
Objective is to produce a set of tables in third-normal form (3NF) because such tables are free of update, insert, and delete anomalies.
Approach is beyond the scope of this book but can be found in any database textbook.
RELATIONAL DATABASES
There are two basic ways to design well-structured relational databases.
Normalization
Semantic data modeling
RELATIONAL DATABASES
Semantic data modeling (covered in detail in Chapter 15)
Database designer uses knowledge about how business processes typically work and the information needs associated with transaction processing to draw a graphical picture of what should be included in the database.
The resulting graphic is used to create a set of relational tables that are in 3NF.
RELATIONAL DATABASES
Advantages over simply following normalization rules:
Semantic data modeling uses the designer’s knowledge about business processes and practices; it therefore facilitates efficient design of transaction processing databases.
The resulting graphical model explicitly represents information about the organization’s business processes and policies and facilitates communication with intended users.
RELATIONAL DATABASES
Creating Relational Database Queries
Databases store data for people and organizations.
To retrieve the data, you query the database and its tables.
Chapter 4 of your textbooks provides some samples of database queries in Microsoft Access.
Try these on your own and/or with your instructor in class.
DATABASE SYSTEMS AND THE FUTURE OF ACCOUNTING
Database systems may profoundly affect the fundamental nature of accounting:
May lead to abandonment of double-entry accounting, because the redundancy of the double entry is not necessary in computer data processing.
May also alter the nature of external reporting.
EXAMPLE: External users could have access to the company’s database and manipulate the data to meet their own reporting needs.
DATABASE SYSTEMS AND THE FUTURE OF ACCOUNTING
The use of accounting information in decision making will be enhanced by:
Powerful querying capabilities that accompany database packages.
The ability to accommodate multiple views of the same underlying phenomenon.
The ability to integrate financial and operational data.
DATABASE SYSTEMS AND THE FUTURE OF ACCOUNTING
Accountants must become knowledgeable about databases so they can participate in developing the AIS of the future.
They must help ensure that adequate controls are included to safeguard the data and assure its reliability.
SUMMARY
You’ve learned how databases differ from file-based legacy systems.
You’ve learned why databases are important and what advantages they offer.
You’ve learned how the logical and physical views of a database differ.
You’ve learned about fundamental concepts of database systems such as DBMS, schemas, the data dictionary, and DBMS languages.
You’ve learned what a relational database is and how it organizes data.
You’ve learned how tables are structured to properly store data in a relational database.