Online Scanner Top Twenty for November 2007

In November, our online statistics returned to their usual state of flux: there are 11 new malicious programs in the Top Twenty, a new leader and it's very unclear what the future may hold.

The eleven newcomers could, potentially, lay the foundation for future statistics. This is especially true of the two classic viruses, Virut.av and Virut.q, which both pose a serious threat and are spreading rapidly. The former took second place in November’s rankings. Given that viruses from this family are also found in the Email Top Twenty, it seems likely that they're here for the duration.

Two worms, Brontok and Rays, have already managed to establish themselves in this way. Despite having been around for years, they remain among the most widespread malicious programs. In November, they easily made it to places in the top six, while October’s leader, Trojan NSAnti.r, has dropped twelve places in a single month.

Dialer.qn, which led our charts several months ago, successfully exploited the current situation to its own advantage. In early 2007, we observed a surge in the number of similar Trojan dialers, but now, as we're moving towards the end of the year, we find that only one has remained in the rankings. This goes to show that survival of the fittest is a principle that works in the IT world, too.

The most widespread adware program, BHO.cc, continues to move up and down the charts. BHO.cc, which is distributed along with BitAccelerator, was first detected in early July. In October, it reached fourth place, but has now dropped six places, only just making it into the Top Ten malicious programs. Nevertheless, it is likely to continue to cause users headaches for a long time to come.

Unexpectedly, Sohanad IM worms have disappeared from the rankings. In October, two of them made the Top Twenty, with one reaching tenth place. But they are no longer around this month; they've been pushed out by seven new programs which occupy positions thirteen to nineteen. These new programs represent all today’s most dangerous malware classes, and include the Trojan-Spy programs OnlineGames.isb and Ardamax.n, two downloaders (.fi and .fx) from the Bagle family, and the file virus Vb.dg. Adware, represented by Virtumonde and BHO, is also among the newcomers.

The distribution of programs in the Top Twenty by class is close to parity: 6 representatives of the VirWare class (Viruses and Worms), 9 TrojWare programs and 4 AdWare programs. The single exception is a ‘semi-legitimate’ keylogger.

It's likely that the situation and overall distribution pattern is likely to remain the same in the coming months, although the proportion of file viruses and adware may increase.

1. New: Virus.Win32.Virut.av, Trojan-Downloader.Win32.Agent.dlu, Trojan.Win32.Agent.cro, Virus.Win32.Virut.q, not-a-virus:AdWare.Win32.Virtumonde.arm, Trojan-Downloader.Win32.Bagle.fi, Trojan-PSW.Win32.OnlineGames.isb, Trojan-Downloader.Win32.Bagle.fx, not-a-virus:AdWare.Win32.BHO.ic, Trojan-Spy.Win32.Ardamax.n, Virus.Win32.VB.dg
2. Moved up: Trojan.Win32.Dialer.qn, not-a-virus:PSWTool.Win32.RAS.a,
3. Moved down: Email-Worm.Win32.Rays, not-a-virus:AdWare.Win32.BHO.cc, Packed.Win32.NSAnti.r, Worm.Win32.AutoIt.c
4. No change: Email-Worm.Win32.Brontok.q, Trojan-Downloader.Win32.Small.ddp.