Summary

Mitglieder is a trojan that functions as an e-mail relay. The trojan kills tasks of several programs and reports certain info to its creators. Bagle worm has the functionality to download and activate this trojan from a website.

Additional Details

When run, the trojan installs itself to system. It copies its file as SYSTEM.EXE to Windows System directory and creates the following entry in the System Registry:

[HKCU\SOFTWARE\Microsoft\Windows\CurrentVersion\Run] "ssgrate.exe" = "%winsysdir%\system.exe"
where %winsysdir% is the name of Windows System directory.

The trojan also creates another entry in the Registry where it stores its internal variables.

Then the trojan starts a thread that accesses 15 different websites and opens a PHP page there with certain parameters. This way the trojan reports its ID, proxy port and IP of infected computers to its authors.

After that trojan starts a thread that terminates processes with the following names:

ATUPDATER.EXE AVWUPD32.EXE AVPUPD.EXE LUALL.EXE DRWEBUPW.EXE ICSSUPPNT.EXE ICSUPP95.EXE UPDATE.EXE NUPGRADE.EXE ATUPDATER.EXE AUPDATE.EXE AUTODOWN.EXE AUTOTRACE.EXE AUTOUPDATE.EXE AVXQUAR.EXE CFIAUDIT.EXE MCUPDATE.EXE NUPGRADE.EXE
The trojan has 3 links in its body that point to a data stealing trojan that is located on 3 different websites. This trojan is detected as 'Trojan.PSW.Ldpinch.as'. The infected files have been recently removed from those website already.

The trojan has a mail relay that functions on the certain port (in the sample we got the port number is 39999).

Detection

Detection for this trojan was was published on January 15th, 2004 in the following update:

[FSAV_Database_Version]
Version=2004-01-15_01

Technical Details: Alexey Podrezov, January 19th, 2004;