A trojan, or trojan horse, is a seemingly legitimate program which secretly performs other, usually malicious, functions. It is usually user-initiated and does not replicate.
Disinfection & Removal
Trojan:W32/Waledac.gen is a Generic Detection of variants in the Trojan:W32/Waledac family. The following details are general characteristics applicable to many, but not all, variants in the Waledac family.
Waledac spreads in an e-mail attachment. Social engineering tricks are used to tempt the victim. Waledac spam frequently uses holidays and news headlines. For example, a fake Barack Obama websites was used as bait during the US 2008 Presidential Elections. Obama spam was also used during the US Presidential Inauguration.
Waledac is capable of receiving commands from a remote server. Commands include instructions on functions to perform (for example, update malware components or send information from the infected computer).Samples analyzed in the lab also downloaded Rogue antispyware applications. Waledac variants use lists of hardcoded IP addresses to determine where it sends harvested data. More recent variants can also update their lists from the remote command server.
The packers used by Waledac are different depending on the variant. Cryptor is being used as of January, 2009.
About Generic Detections
Unlike more traditional detections (also known as signatures or single-file detections) a Generic Detection does not identify a unique or individual malicious program. Instead, a Generic Detection looks for broadly applicable code or behavior characteristics that indicate a file as potentially malicious, so that a single Generic Detection can efficiently identify dozens, or even hundreds of malware.