Atak was first discovered Monday. Although antivirus companies do not expect it to cause much damage, they say it will be a nuisance because it can generate a large amount of spam.
Graham Cluley, senior technology consultant for antivirus company Sophos, said authors of malicious software generally try to make the job of antivirus researchers as difficult as possible by adding confusing code and using evasion techniques.
"Atak tries to tell when someone is stepping through the code to analyze whether it is a virus or not. Often, a virus will contain lots of code that is designed to make it more complicated for (antivirus) companies to write the detections," Cluley said.