TR/Drop.OnGa.AZ - Trojan

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Summary

Full description

Statistics

Virus:	TR/Drop.OnGa.AZ
Date discovered:	02/03/2009
Type:	Trojan
In the wild:	Yes
Reported Infections:	Low
Distribution Potential:	Medium
Damage Potential:	Medium to high
Static file:	Yes
File size:	107.295 Bytes
MD5 checksum:	ff6b14d521a4c613754b47d754672d63
IVDF version:	7.01.02.103 - Mon, 02 Mar 2009 15:42 (GMT+1)

General Methods of propagation:
   • Mapped network drives

Aliases:
   • Symantec: W32.Gammima.AG
   • Sophos: W32/Autorun-AAP
   • Panda: W32/Lineage.KPH
   • Grisoft: PSW.OnlineGames.2.S
   • Eset: Win32/PSW.OnLineGames.NMY

Platforms / OS:
   • Windows 2000
   • Windows XP
   • Windows 2003

Side effects:
   • Downloads a malicious file
   • Drops malicious files
   • Lowers security settings
   • Registry modification

Files It copies itself to the following locations:
   • %SYSDIR%\ierdfgh.exe
   • %drive%\y6.exe

It deletes the initially executed copy of itself.

It deletes the following file:
   • %SYSDIR%\drivers\cdaudio.sys

It may corrupt the following file:
   • %SYSDIR%\drivers\cdaudio.sys

The following files are created:

– %drive%\autorun.inf This is a non malicious text file with the following content:
   • %code that runs malware%

– %SYSDIR%\pytdfse%number%.dll Further investigation pointed out that this file is malware, too.
– %SYSDIR%\drivers\klif.sys
– %TEMPDIR%\4tddfwq0.dll
– %TEMPDIR%\xvassdf.exe

It tries to download a file:

– The location is the following:
   • http://vfbgt.com/xrbv/**********
At the time of writing this file was not online for further investigation.

– The location is the following:
   • http://sfdght.com/xrbv/**********

Registry One of the following values is added in order to run the process after reboot:

– [HKCU\Software\Microsoft\Windows\CurrentVersion\Run]
   • "kxswsoft"="%SYSDIR%\ierdfgh.exe"

The following registry keys are changed:

– [HKLM\SOFTWARE\KasperskyLab\protected\AVP7\profiles\Updater]
   New value:
   • "enabled"=dword:00000000

Various Explorer settings:
– [HKCU\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer]
   New value:
   • "NoDriveTypeAutoRun"=dword:00000091

– [HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Advanced\
   Folder\Hidden\SHOWALL]
   New value:
   • "CheckedValue"=dword:00000001

– [HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced]
   New value:
   • "ShowSuperHidden"=dword:00000001
     "Hidden"=dword:00000002

Injection – It injects the following file into a process: %SYSDIR%\pytdfse%number%.dll

– It injects a process watching routine into a process.

    Process name:
   • explorer.exe

   If the malware fails, it continues running as a process.

Rootkit Technology It is a malware-specific technology. The malware hides its presence from system utilities, security applications and in the end, from the user.

Method used:
• Hidden from Windows API
• Hidden from Interrupt Descriptor Table (IDT)

File details Programming language:
The malware program was written in MS Visual C++.

Runtime packer:
In order to aggravate detection and reduce size of the file it is packed with a runtime packer.

See a brief description here.

Description inserted by Petre Galan on Mon, 06 Jul 2009 21:36 (GMT+1)
Description updated by Petre Galan on Tue, 18 Aug 2009 11:44 (GMT+1)

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