Computer Virus
Author: CHAYAN SUR
In 1983, Fred Cohen coined the term “computer virusâ€, postulating a virus was "a program that can 'infect' other programs by
modifying them to include a possibly evolved copy of itself.†The term virus is actually an acronym for Vital Information Resources
Under Seize. Mr. Cohen expanded his definition a year later in his 1984 paper, “A Computer Virusâ€, noting that “a virus can
spread throughout a computer system or network using the authorizations of every user using it to infect their programs. Every program
that gets infected may also act as a virus and thus the infection grows.†Computer viruses, as we know them now, originated in 1986
with the creation of Brain - the first virus for personal computers. Two brothers wrote it (Basid and Farooq Alvi who ran a small software
house in Lahore, Pakistan) and started the race between viruses and anti-virus programs which still goes on today.
Using the above explanation, it can be said that viruses infect program files. However, viruses can also infect certain types of data files,
specifically those types of data files that support executable content, for example, files created in Microsoft Office programs that rely on
macros.
Compounding the definition difficulty, viruses also exist that demonstrate a similar ability to infect data files that don't typically support
executable content - for example, Adobe PDF files, widely used for document sharing, and .JPG image files. However, in both cases, the
respective virus has a dependency on an outside executable and thus neither virus can be considered more than a simple ‘proof of
concept’. In other cases, the data files themselves may not be infectable, but can allow for the introduction of viral code. Specifically,
vulnerabilities in certain products can allow data files to be manipulated in such a way that it will cause the host program to become
unstable, after which malicious code can be introduced to the system. These examples are given simply to note that viruses no