“ A logic bomb, also known as a "time bomb", is another technique by which computer sabotage can be perpetrated. The creation of logic bombs requires some specialized knowledge, as it involves programming the destruction or modification of data at a specific time in the future. Unlike viruses or worms, however, logic bombs are very difficult to detect before they blow up; thus, of all these computer crime schemes, they have the greatest potential for damage. ”

“ Computer fraud by input manipulation is the most common computer crime, as it is easily perpetrated and difficult to detect. Often referred to as "data diddling", it does not require any sophisticated computer knowledge and can be committed by anyone having access to normal data-processing functions at the input stage. ”

“ Intangible assets represented in data format, such as money on deposit or hours of work, are the most common targets of computer-related fraud. Modern business is quickly replacing cash with deposits transacted on computer systems, creating an enormous potential for computer abuse. Credit card information, as well as personal and financial information on credit-card clients, have been frequently targeted by the organized criminal community. The sale of this information to counterfeiters of credit cards and travel documents has proven to be extremely lucrative. ”

“ A common method used by persons with specialized knowledge of computer programming is the trojan horse, whereby computer instructions are covertly placed in a computer program so that it will perform an unauthorized function concurrent with its normal function. A trojan horse can be programmed to self-destruct, leaving no evidence of its existence except the damage that it caused. 13 Remote access capabilities today also allow the criminal to easily run modified routines concurrently with legitimate programs. ”

“ Modern telecommunications systems are equally vulnerable to criminal activity. Office automation systems such as voice mail boxes and private business exchanges are, in effect, computer systems, designed for the convenience of users. However, convenience features such as remote access and maintenance capabilities, call-forwarding and voice-messaging are easily infiltrated by computer criminals. ”

“ Program manipulation, which is very difficult to discover and is frequently not recognized, requires the perpetrator to have computer-specific knowledge. It involves changing existing programs in the computer system or inserting new programs or routines. ”

“ All stages of computer operations are susceptible to criminal activity, either as the target of the crime or the instrument of the crime or both. Input operations, data processing, output operations and communications have all been utilized for illicit purposes. The more common types of computer-related crime are categorized next. ”

“ Frequently, hackers impersonate legitimate system users; this is especially common in systems where users can employ common passwords or maintenance passwords found in the system itself.
76. Password protection is often mischaracterized as a protective device against unauthorized access. However, the modern hacker can easily circumvent this protection using one of three common methods. If a hacker is able to discover a password allowing access, then a trojan horse program can be placed to capture the other passwords of legitimate users. ”

“ Access is often accomplished from a remote location along a telecommunication network, by one of several means. The perpetrator may be able to take advantage of lax security measures to gain access or may find loopholes in existing security measures or system procedures. ”

“ Assets represented in data format often have a considerably higher value than traditionally targeted economic assets, resulting in potentially greater economic loss. In addition, improved remote access to databases allows the criminal the opportunity to commit various types of fraud without ever physically entering the premises of the victim. ”

“ A new generation of fraudulent alteration or counterfeiting emerged when computerized colour laser copiers became available. 14 These copiers are capable of high-resolution copying, the modification of documents and even the creation of false documents without benefit of an original, and they produce documents whose quality is indistinguishable from that of authentic documents except by an expert. ”

“ Detonation can be timed to cause maximum damage and to take place long after the departure of the perpetrator. The logic bomb may also be used as a tool of extortion, with a ransom being demanded in exchange for disclosure of the location of the bomb. ”