Common Types of Viruses
➢ Trojan Horses –
A Trojan Horse are computer viruses that hide inside non-executable files such as compressed or document files and executable files and try to avoid detection by anti-virus programs such as Norton or McAfee. Trojan Horses usually appear to be useful computer files/programs such as computer game or data library. Famous Trojan Horse Programs
o Back Orifice
Latest Trojan Horses News
o Trojan.Pgpcoder – unique new kind of threat – Install itself on vulnerable computer after user visit a certain website.
➢ Polymorphic Viruses
A polymorphic virus is an encrypted virus that hides itself from anti-virus trough encrypted (scrambled) data and then decrypted itself to be able to spread trough the computer. The thing that makes it hard for anti-virus software to detect polymorphic viruses is that the virus generates an entirely new decryption routine each time it infects a new executable file making the virus signature different in each signature.
➢ Stealth Viruses
A stealth virus hides the modifications made to file and boot records by modifying and forging the result of calls to function, therefore programs believe they are reading the original file and not the modified file. A good anti-virus software will probably detect stealth virus due to the fact that a stealth virus attempts to hide itself in memory when anti-virus software is launched.
➢ Slow Viruses
A Slow virus is a difficult virus to detect due to the fact it only modifies and infects files when they are been modified and copied. Therefore the original file will not be infected by the actual copied file. A good way to protect yourself against slow viruses is by using an integrity checker or shell.
➢ Retro Viruses
A Retro virus attacks the anti-virus software designed to delete it. The retro virus usually attempts to attack the anti-virus data files...
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