A Matter of Timing

Some hackers program viruses to sit dormant on a victim's computer only to unleash an attack on a specific date. Here's a quick sample of some famous viruses that had time triggers:

ñ The Jerusalem virus activated every Friday the 13th to destroy data on the victim computer's hard drive

ñ The Michelangelo virus activated on March 6, 1992 -- Michelangelo was born on March 6, 1475

ñ The Chernobyl virus activated on April 26, 1999 -- the 13th anniversary of the Chernobyl meltdown disaster

ñ The Nyxem virus delivered its payload on the third of every month, wiping out files on the victim's computer

Computer viruses can make a victim feel helpless, vulnerable and despondent. Next, we'll look at a virus with a name that evokes all three of those feelings.

Worst Computer Virus 4: MyDoom

The MyDoom (or Novarg) virus is another worm that can create a backdoor in the victim computer's operating system. The original MyDoom virus -- there have been several variants -- had two triggers. One trigger caused the virus to begin a denial of service (DoS) attack starting Feb. 1, 2004. The second trigger commanded the virus to stop distributing itself on Feb. 12, 2004. Even after the virus stopped spreading, the backdoors created during the initial infections remained active [source: Symantec].

Later that year, a second outbreak of the MyDoom virus gave severalsearch engine companies grief. Like other viruses, MyDoom searched victim computers for e-mail addresses as part of its replication process. But it would also send a search request to a search engine and use e-mail addresses found in the search results. Eventually, search engines like Google began to receive millions of search requests from corrupted computers. These attacks slowed down search engine services and even caused some to crash [source:Sullivan].

MyDoom spread through e-mail and peer-to-peer networks. According to the security firm MessageLabs, one in every 12 e-mail messages carried the virus at one time [source: BBC]. Like the Klez virus, MyDoom could spoof e-mails so that it became very difficult to track the source of the infection.

Date: 2015-04-20; view: 715