The McAfee Threats Report for the first quarter of 2013 highlighted a noteworthy increase in the number of Koobface malware samples on record. This data point is based on the number of unique malicious files associated with the Koobface family, and is generally one indicator of active malware development.

Besides the number of changes made to a malware’s code base, sample counts can also be influenced by repacking of the same underlying code (a common evasion tactic used by malware distributors), garbage data or junk instructions added to binaries, and other forms of server or client polymorphisms (such as self-modifying code or web server scripts that result in a unique binary being served with each download). Another complication arises from what is often called a cocktail, in which a parasitic virus inhabits a host file that is itself another piece of malware.

These factors led to McAfee Koobface statistics being off by a large margin. The corrected data below shows Koobface on a continuing decline since Facebook published its landmark post “Facebook’s Continued Fight Against Koobface” nearly a year and a half ago.



McAfee publicly apologized for the error in their blog post.