Online Scanner Top Twenty for September 2007

Position	Change in position	Name	Percentage
1.	+1	Trojan.Win32.Dialer.qn	1.65
2.	+1	Trojan-Downloader.Win32.LoadAdv.gen	1.56
3.	+1	Email-Worm.Win32.Brontok.q	1.50
4.	+4	Trojan-Downloader.Win32.Small.ddp	1.34
5.	+7	not-a-virus:Monitor.Win32.Perflogger.ca	1.30
6.	+4	Email-Worm.Win32.Rays	1.28
7.	+2	not-a-virus:PSWTool.Win32.RAS.a	1.27
8.	+11	Virus.VBS.Small.a	1.26
9.	New	not-a-virus:AdWare.Win32.BHO.cc	1.17
10.	+1	not-a-virus:AdWare.Win32.Virtumonde.jp	1.03
11.	+7	not-a-virus:Monitor.Win32.Perflogger.ad	0.88
12.	+5	IM-Worm.Win32.Sohanad.t	0.78
13.	New	Trojan-Spy.Win32.Perfloger.ab	0.73
14.	+6	Trojan.Win32.Obfuscated.en	0.73
15.	New	IM-Worm.Win32.Sohanad.as	0.69
16.	New	Trojan.Win32.Delf.aam	0.59
17.	New	Worm.Win32.AutoIt.c	0.57
18.	-17	Packed.Win32.PolyCrypt.b	0.55
19.	New	not-a-virus:AdWare.Win32.Agent.bm	0.53
20.	New	not-a-virus:Dialer.Win32.Agent.b	0.51
Other malicious programs			80.08%

The Brontok and Rays worms are still steadily working their way back to the leading positions in online ratings. In September, Brontok managed a place in the top three after having disappeared from the Top Twenty altogether. Meanwhile, Rays climbed another four positions and reached sixth place, after being placed twentieth in July.

September’s Online Top Twenty was a little unusual in terms of the movement of the entries. Only one program fell in the rankings: PolyCrypt.b, the leader in August, fell seventeen places. All of the others increased their rankings. The leader of the month in terms of growth is VBS.Small.a, a script virus which climbed eleven positions to reach eighth place.

The real leaders didn’t undergo much change in the last four weeks. Dialer.qn, a Trojan dialer program, reached first place, with second place being taken by LoadAdv.gen, a Trojan that downloads adware. This is the program that carried a number of other programs with it into the Online Top Twenty this month, such as not-a-virus:AdWare.Win32.Virtumonde.jp and a newcomer - not-a-virus:AdWare.Win32.BHO.cc.

Trojan.Downloader.Win32.Small.ddp continued to climb the rankings in September. In August, this program made a comeback to the Top Twenty, and already made it to fourth place the following month. Considering that this program is meant to install a number of malicious components on infected computers as part of a botnet, we can expect the launch of another epidemic caused by the related Zbot Trojan family (a.k.a Bancos.aam) in the near future.

Interestingly, seven positions are filled this month by programs that fall into the not-a-virus class: three adware programs, two monitoring programs, one so-called password restorer and one legitimate dialer program.

Surprisingly, Trojan Spies have only one representative on the Online chart in September – a modification of Perflogger, a legitimate keylogging program. Meanwhile, there are plenty of worms in sight. In addition to the already mentioned Brontok and Rays worms, the September rankings also feature two worms for Instant Messenger Sohanad (.t and .as) and Worm.Win32.Autoit.c.

Summary

• New: not-a-virus:AdWare.Win32.BHO.cc, Trojan-Spy.Win32.Perfloger.ab, IM-Worm.Win32.Sohanad.as, Trojan.Win32.Delf.aam, Worm.Win32.AutoIt.c, not-a-virus:AdWare.Win32.Agent.bm, not-a-virus:Dialer.Win32.Agent.b
• Moved up: Trojan.Win32.Dialer.qn, Trojan-Downloader.Win32.LoadAdv.gen, Email-Worm.Win32.Brontok.q, Trojan-Downloader.Win32.Small.ddp, not-a-virus:Monitor.Win32.Perflogger.ca, Email-Worm.Win32.Rays, not-a-virus:PSWTool.Win32.RAS.a, Virus.VBS.Small.a, not-a-virus:AdWare.Win32.Virtumonde.jp, not-a-virus:Monitor.Win32.Perflogger.ad, IM-Worm.Win32.Sohanad.t, Trojan.Win32.Obfuscated.en
• Moved down: Packed.Win32.PolyCrypt.b