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An overview of computer
viruses
Controlling against computer
viruses
Examples of Viruses
The following are some more examples of
viruses:
- 2 Joke.Geschen - The GESCHENK
Trojan is not a virus. This program will not perform malicious actions
on a computer and is a "joke program." Joke programs are
programs that attempt to display something humorous or pretend to
perform a malicious action. When run, this program will open your
CD-ROM drive tray. Delete or ignore the file.
- Wobbling - The Wobbling trojan
was a simple joke program that was mistakenly identified as a Trojan.
It does nothing other than cause all open windows on the desktop to
wobble as if in an earthquake.
- Parity Boot.B - This boot virus
has a medium-risk. The Parity Boot. B virus is quite common and can be
found all over the world. The severity of any malicious actions, or
payload, is medium rating. If there is no key pressed for a long time,
Parity Boot. B only displays a message and freezes the machine. As a
pure boot virus, it uses an infection vehicle that loses more and more
importance. Different factors steadily decrease the risk of this
virus. The current trend of modern IT infrastructure is to store and
transfer data using file servers, e-mail, and ftp, as well as build
operating system architecture which limits the ability of boot viruses
to execute. Boot viruses will become very rare in modern IT
environments and will change to become only a low-risk.
- XM.Compat.A - This macro virus
was assigned a high-risk rating initially. It was sporadically
reported and its payload caused very serious damage by manipulating
cell values in spreadsheets. At the time, Microsoft Excel 5 and 7 were
commonly used spreadsheet platforms.
- W95/ CIH - CIH is one of the most
known and feared viruses since it first appeared in the summer of
1998. It is a high-risk rating. Many infections were reported and it
was very widespread, initially, through pirated software and Internet
downloads. When the virus payload triggers, it erases data on the hard
disk and tries to overwrite the computer system BIOS, potentially
leaving the machine unusable. This payload is considered very serious.
By running on Windows 95/ 98 systems, the virus infects a very common
operating platform. The CIH virus was one of the first functional
Windows viruses, which is a special contributing factor.
- Happy99.Worm - This is a worm
virus. It attaches itself to outgoing e-mail by modifying the Windows
system file, WSOCK32. DLL. Thus, its infection vehicle is a Windows
machine, although with Windows NT systems, this infection normally
fails. It has achieved a very high prevalence. Its payload displays a
fireworks graphic when the attachment HAPPY99. EXE is run producing
little damage, but causing users to have to re-send the message.
Because of the payload, the worm is assigned as a medium-risk rating
rather than a high-risk.
- W97M/Melissa.A - This macro virus
infects Word 97 documents and sends itself by e-mail to the first fifty
recipients in each Outlook address book. Since its payload does little
damage, although the virus may insert some text, it was assigned a
high-risk rating because of its infection technique. Melissa caused
damage indirectly by overloading mail servers that consequently have
to be shut down.
- W32/ExploreZip.worm - This is a
very dangerous worm spreading by e-mail and through in-house network
shares. Its specific factors made its already dangerous infection
technique even more successful. It replies to incoming mails and
attaches itself as ZIPPED_ FILES. EXE. The mail text makes the user
believe this would be a self-extracting ZIP archive. It also has a
very serious payload which can delete file types like Word documents,
Excel workbooks, PowerPoint presentations and source code files on all
available drives. All this together leads to a high-risk rating.
There have been many others, details of
which can be found at the following Internet web sites:
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