Computer viruses in November

Last month, Hungary's computer virus landscape was dominated by malicious programs, which download other malicious programs, according to VirusBuster's stats.

The Hungary-based specialist of IT security continuously monitors virus occurrence and activity. Data from VirusBuster's mail protection systems -- in-house and externally deployed alike -- is collected, and Freemail, a major Hungarian free webmail service is also monitored for malicious load. VirusBuster uses all these sources to generate monthly statistics of the most frequent infections. These monthly virus toplists are published on the company's website as well (http://www.virusbuster.hu/en/viruslab/virus-toplist).

November's toplist (see below) has three Sasfis variants. Trojan.Sasfis.AZT in itself was observed in more than half of all virus occurences. "These programs are called downloaders. Hiding on the victim's machine, they wait for their master's commands and download other malicious programs (malware)", explains Gábor Szappanos, the head of VirusBuster's virus lab.

IRCBot variants also played an important role last month. The different IRCBots, as well as Worm.SdBot.GAP belong to the family of "botnet" (=robot network) malware, i.e. they organize PCs into networks controlled by hackers. Users normally don't even notice the infection. No wonder that botnet member machines are called "zombies". However, once users detect the infection, they should remove the malware as soon as possible. "Otherwise, unknowingly, they may become accomplices in cybercriminals' activities", Gábor Szappanos warned.

VirusBuster's malware toplist for November 2009: