Antivirus experts have identified new versions of three major email worms and say that a 'war' between rival virus writers may be to blame for the rash of outbreaks in recent weeks.
New versions of the Mydoom, Netsky, and Bagle have all appeared on the internet in the last 48 hours.
Antivirus researchers have uncovered text messages in two of the worms that suggest a battle is underway between virus writers, according to antivirus companies.
Examples of Netsky.F, Bagle.K ,and Mydoom.H were isolated on Wednesday, according to antivirus company F-Secure.
All three variants resemble their predecessors, which spread in email messages with vague-sounding subjects using infected attachments such as .zip, .exe, or .pif files.
The viruses have their own SMTP engines and harvest email addresses from infected computers, which are then targeted with infected mail.
The Bagle and Mydoom worms also open communication ports on infected systems which can be used by remote attackers to route unsolicited commercial ("spam") email, send malicious instructions to the computer, or install remote monitoring software, according to Al Huger, senior director of engineering for security response at Symantec.
Bagle.J, Bagle.K, Netsky.F, and Mydoom.G also contain comments that are part of a spirited dialogue between virus authors, according to antivirus company Sophos.
Text comments in the worm code are preserved in the binary format file that is created when the code is "compiled," or turned into a computer program that can be run, accordong to Huger.
Spiced with foul language and bad spelling, the messages portray a playground-style brawl between the authors, with the internet worms acting as messengers.
"Hey, Netsky...don't ruine (sp) our bussiness (sp), wanna start a war?" reads a message in the Bagle.J worm's code, according to Sophos.
A message found in Netsky.F reads: "Skynet AntiVirus - Bagle - you are a looser (sp)!!!!," and the recent Mydoom.G virus also includes hidden comments critical of the Netsky worm, according to F-Secure.
The back and forth flak between virus authors started in January when Netsky began removing the Mydoom and Bagle viruses from machines it infected, according to Huger.
The spat has escalated in recent weeks, with multiple versions of the Bagle and Netsky worms appearing on an almost daily basis, primarily as vehicles for delivering new barbs and insults from the authors, according to Huger.
Sparring matches between virus writers and hackers are nothing new, however the seriousness of the recent outbreaks has put this shouting match in the public eye.
"This behavior isn't new. The hacking community has been doing this for years," he says.
The exchanges have been amusing to weary antivirus researchers, who are also hopeful that they might lead to the capture of one or more of the worm authors.
"The more they talk, the more the open up chances to get caught," Huger says.