A COM file is a type of simple executable file. On the Digital Equipment Corporation (DEC) VAX operating systems of the 1970s, .COM was used as a filename extension for text files containing commands to be issued to the operating system. With the introduction of Digital Research's CP/M, the type of files commonly associated with COM extension changed to that of executable files. This convention was later carried over to DOS. Even when complemented by the more general EXE file format for executables, the compact COM files remained viable and frequently used under DOS.
Abraxas, also known as Abraxas5, discovered in April 1993, is an encrypted, overwriting, file infecting computer virus which infects .COM and .EXE files, although it does not infect command.com. It does not become memory resident. Each time an infected file is executed, Abraxas infects the copy of dosshell.com located in the C:\DOS directory, as well as one EXE file in the current directory. Due to a bug in the virus, only the first EXE file in any directory is infected.
Acme is a computer virus which infects MS-DOS EXE files. Each time an infected file is executed, Acme may infect an EXE in the current directory by creating a hidden 247 byte long read-only COM file with the same base name. Acme is a variant of Clonewar, a spawning virus. Acme is also perhaps a descendant of the small single-step infector Zeno, which is not to be confused with the Zeno programming language.
AIDS is a DOS computer virus which overwrites COM files.
ABC, discovered in October 1992, is a memory-resident, file-infecting computer virus which infects EXE files and may alter both COM and EXE files. ABC activates on the 13th day of every month.
Jerusalem is a logic bomb DOS virus first detected at Hebrew University of Jerusalem, in October 1987. On infection, the Jerusalem virus becomes memory resident, and then infects every executable file run, except for COMMAND.COM. COM files grow by 1,813 bytes when infected by Jerusalem and are not re-infected. Executable files grow by 1,808 to 1,823 bytes each time they are infected, and are then re-infected each time the files are loaded until they are too large to load into memory. Some .EXE files are infected but do not grow because several overlays follow the genuine .EXE file in the same file. Sometimes .EXE files are incorrectly infected, causing the program to fail to run as soon as it is executed.
Westwood is a computer virus, a variant of the Jerusalem family, discovered August 1990, in Westwood, Los Angeles, California. The virus was isolated by a UCLA engineering student who discovered it in a copy of the "speed.com" program distributed with a new motherboard. Viral infection was first indicated when an early version of Microsoft Word reported internal checksum failure and failed to run.
Scott's Valley [sic] is a computer virus, a member of the Slow virus family and distantly related to the Jerusalem virus family. It was discovered in September 1990 in Scotts Valley, California.
Sunday is a computer virus, a member of the Jerusalem virus family. It was discovered in November 1989 after a number of simultaneous reports from Seattle, Washington, United States, and surrounding areas. Several other Seattle outbreaks, including AirCop, were later traced to Asia.
Alabama is a computer virus, discovered in October 1989 on the campus of the Hebrew University of Jerusalem.
Ontario is a family of computer viruses, named after its point of isolation, the Canadian province of Ontario. This family of computer virus consists of Ontario.1024, Ontario.512 and Ontario.2048. The first variant Ontario.512 was discovered in July 1990. Because Ontario.1024 was also discovered in Ontario, it is likely that both viruses originate from within the province. By the Ontario.2048 variant, the author had adopted "Ontario" as the family's name and even included the name "Ontario-3" in the virus code.
CTX is a computer virus created in Spain in 1999. CTX was initially discovered as part of the Cholera worm, with which the author intentionally infected with CTX. Although the Cholera worm had the capability to send itself via email, the CTX worm quickly surpassed it in prevalence. Cholera is now considered obsolete, while CTX remains in the field, albeit with only rare discoveries.
The Vundo Trojan is either a Trojan horse or a computer worm that is known to cause popups and advertising for rogue antispyware programs, and sporadically other misbehavior including performance degradation and denial of service with some websites including Google and Facebook. It also is used to deliver other malware to its host computers. Later versions include rootkits and ransomware.
W32.Navidad is a mass-mailing worm program or virus, discovered in December 2000 that ran on Windows 95, Windows 98, Windows NT, and Windows 2000 systems. It was designed to spread through email clients such as Microsoft Outlook while masquerading as an executable electronic Christmas card. Infected computers can be identified by blue eye icons which appear in the Windows system tray.
Eliza is a computer virus discovered in December 1991. It infects COM files including COMMAND.COM. It has been reported that it is defective, yet destroys the .EXE files it creates. The .COM files are not deleted. To avoid detection, it does not alter the dates of files it infects, but increases their length by 1,193 or 1,194 bytes. It is also found in later versions of Windows.
5lo is a computer virus that increases file size and does little more than replicate. Size: 1,032 bytes
KoKo Virus is a memory resident computer virus created in March 1991. KoKo's name came from the creator himself, which was a nickname used by his friends. Many on-line virus databases refer to KoKo as Koko.1780. KoKo is written in the Assembly programming language and the executable file usually has an approximate file size of around 1780 bytes.
MS Antivirus is a scareware rogue anti-virus which purports to remove virus infections found on a computer running Microsoft Windows. It attempts to scam the user into purchasing a "full version" of the software. The company and the individuals behind Bakasoftware operated under other different 'company' names, including Innovagest2000, Innovative Marketing Ukraine, Pandora Software, LocusSoftware, etc.
Sality is the classification for a family of malicious software (malware), which infects Microsoft Windows systems files. Sality was first discovered in 2003 and has advanced to become a dynamic, enduring and full-featured form of malicious code. Systems infected with Sality may communicate over a peer-to-peer (P2P) network to form a botnet to relay spam, proxying of communications, exfiltrating sensitive data, compromising web servers and/or coordinating distributed computing tasks to process intensive tasks. Since 2010, certain variants of Sality have also incorporated rootkit functions as part of an ongoing evolution of the malware family. Because of its continued development and capabilities, Sality is considered one of the most complex and formidable forms of malware to date.
Slenfbot is the classification for a family of malicious software (malware), which infects files on Microsoft Windows systems. Slenfbot was first discovered in 2007 and, since then, numerous variants have followed; each with slightly different characteristics and new additions to the worm's payload, such as the ability to provide the attacker with unauthorized access to the compromised host. Slenfbot primarily spreads by luring users to follow links to websites, which contain a malicious payload. Slenfbot propagates via instant messaging applications, removable drives and/or the local network via network shares. The code for Slenfbot appears to be closely managed, which may provide attribution to a single group and/or indicate that a large portion of the code is shared amongst multiple groups. The inclusion of other malware families and variants as well as its own continuous evolution, makes Slenfbot a highly effective downloader with a propensity to cause even more damage to compromised systems.
