MyDoom-O worm attacks Google and other internet search engines, Sophos reports

July 27, 2004 Sophos Press Release


Google is one of the internet search engines used by the MyDoom-O worm

Google whacked by internet worm

Virus experts at Sophos have reported that millions of computer users around the globe found their access to the world's most popular internet search engine, Google, disrupted by the W32/MyDoom-O worm yesterday.

The MyDoom-O worm has been spreading widely across internet email systems, duping innocent users into launching its malicious attachment.

If run, the worm not only attempts to scoop up addresses to send itself to from the infected user's hard drive, but can also use the internet search engines Google, Altavista, Lycos and Yahoo to hunt for other email addresses.

"This is unprecedented - no virus has ever used internet search engines before in their attempt to find other email addresses to send itself to," said Graham Cluley, senior technology consultant for Sophos. "The effect on Google was considerable - for a few hours millions saw an error message whenever they tried to search. Whether the virus intended it or not, it denied many users access to one of the internet's most popular features."

A Google spokesperson confirmed the disruption in a statement to the press, "The Google search engine experienced slowness for a short period of time because of the MyDoom virus, which flooded major search engines with automated searches."

Sophos notes that Google was not the only search engine which could be used by the MyDoom-O worm, but was the most likely to be accessed. Coded inside MyDoom-O is the ability to use the Altavista, Lycos or Yahoo search engines to hunt for email addresses as well as Google, but the decision as to which to use is made via a probability calculation:

  • www.google.com (45%)
  • search.lycos.com (22.5%)
  • search.yahoo.com (20%)
  • www.altavista.com (12.5%)

"For whatever reason the virus author has ranked the internet search engines, and chosen which ones they want the worm to use most of the time - Google and Lycos," continued Cluley. "By using internet search engines in this way the worm's creator is effectively attempting a kind of denial of service attack against these websites."