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 processed. VirusBuster uses the results 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).

"Last month's catch was particularly interesting", says Gábor Szappanos, the head of VirusBuster's virus lab. "Nine out of the ten most frequent malicious programs were trojans designed to download fake antivirus applications onto the victim's machine."

Trojans, mentioned above, are malicious programs, which got their name from the legendary wooden horse built by the Greeks to defeat Troy: They pretend to serve users, but in fact they are designed to cheat their victims.

VirusBuster's March trojan ringleaders set off (fake) alarm bells warning the user of a virus infection, and then download a rogue antivirus application, i.e. a program, which promises to clean the machine, but which, in reality, either does nothing (the better option), or starts some malicious activity. The user is often charged for such a download, so these trojans are, in fact, tools for fraud. They mostly come in e-mail attachments. Spammers disguise them as some useful file, such as an order confirmation. But beware! Opening the attachment launches the infection mechanism.

The only different program on last month's toplist, Backdoor.Bandok.GT (#7, with approximately 5% share), belongs to the family of botnet malware. Botnets are networks of unknowing victim PCs (called zombies), which are controlled by hackers. Users should get rid of botnet malware as soon as possible, since otherwise they may become accomplices in the cybercriminals' activities, warns Gábor Szappanos.

VirusBuster's malware toplist for March 2010:

Malware Share (%)
Trojan.Kryptik.LTJ 18.90%
Trojan.DigiPog.BV 15.94%
Trojan.FakeAV.TF 13.91%
Trojan.Kryptik.MJR 13.54%
Trojan.FraudPack.YEC 8.74%
Trojan.FakeRean.WO 8.66%
Backdoor.Bandok.GT 4.87%
Trojan.FakeAV.TH 3.90%
Trojan.Oficla.AJY 2.96%
Trojan.FraudPack.ZGF 1.12%
Other: 7.46%"

Source: Virus Buster