Classification

Category :

Malware

Type :

Trojan

Aliases :

Dasmin, Trojan.Win32.Dasmin, Trojan.Dasmin, TROJ_DASMIN, Poldo

Summary

Dasmin is a simple UPX-packed trojan that installs itself to Windows System folder as 2 separate files:

jdbgmrg.exe
avirchk.exe

It should be noted that the trojan uses the 'jdbgmrg.exe' name that is quite close to the name of a common Windows component: 'jdbgmgr.exe' (Java Debug Manager). Also one Jdbgmgr hoax variant that was widespread in May 2002 had a typo - there was 'jdbgmrg.exe' file name mentioned there while it should have been 'jdbgmgr.exe' name. Also please note that the Dasmin trojan uses the same 'teddy bear' icon that looks exactly like the icon of JDBGMBR.EXE file.

The trojan creates autostartup keys for itself in the Registry. It also changes startup and search pages of Internet Explorer.

Removal

To disinfect a system from this trojan it's enough to kill trojan's tasks from Task Manager and to delete both trojan's files from a hard drive.

A False Positive is when a file is incorrectly detected as harmful, usually because its code or behavior resembles known harmful programs. A False Positive will usually be fixed in a subsequent database update without any action needed on your part. If you wish, you may also:

  • Check for the latest database updates

    First check if your F-Secure security program is using the latest updates, then try scanning the file again.

  • Submit a sample

    After checking, if you still believe the file is incorrectly detected, you can submit a sample of it for re-analysis.

    Note: If the file was moved to quarantine, you need to collect the file from quarantine before you can submit it.

  • Exclude a file from further scanning

    If you are certain that the file is safe and want to continue using it, you can exclude it from further scanning by the F-Secure security product.

    Note: You need administrative rights to change the settings.

Technical Details

Variant:Dasmin.B (Trojan.Win32.Dasmin.B)

In the beginning of January 2003 there also appeared a new variant of Dasmin trojan. It also installed itself twice, but with different names:

REGCPM32.EXE
IEXPRES.EXE

Like its ancestor, the trojan created startup keys for its files in System Registry.

Variant:Dasmin.C (Trojan.Win32.Virgilio, Trojan.Win32.Dasmin.C)

Almost at the same time with Dasmin.B there appeared a bit modified variant of the trojan. It installed itself to system once and with a different name:

MSFINDOSA.EXE

It also created a startup key for its file in the Registry.