When a PC gets infected, the worm will connect to the Gnutella network as one node. After that it will monitor what kind of files other people are searching for, and will answer those queries.
For example, if a Gnutella user makes search for "rare pictures of butterflies", the infected node will announce it has available a file called "rare pictures of butterflies.exe", 8kB in size.
If the user downloads and clicks on this file, his machine becomes infected and will start to offer infected files for other users.
Infected nodes easily become overloaded and are unable to answer all requests. So every search does not find infected files although there are infected nodes in the network.
In some cases, infected files are offered without the EXE extension. Such files will fail to execute when doubleclicked but work fine if run from the commandline.
First infected files in the Gnutella network were spotted on Friday the 23rd of February, 2001.
An easy way to avoid infection from this worm is not to download EXE files from the Gnutella network. Some clients (such as BearShare) hide executable files from seach results by default.
For more information, see:
F-Secure Anti-Virus detects this virus since Tuesday, 27th of February. The updates are available on our web site:
[Mikko Hypponen, F-Secure Corporation, Feb 27, 2001]