Worm/Sohanad.S - Worm

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Summary

Full description

Statistics

Virus:	Worm/Sohanad.S
Date discovered:	01/09/2008
Type:	Worm
In the wild:	Yes
Reported Infections:	Low to medium
Distribution Potential:	Low to medium
Damage Potential:	Low to medium
Static file:	Yes
File size:	315.905 Bytes
MD5 checksum:	37091432f5e73c8f0E407c10a0b0b84f
VDF version:	7.00.06.99 - Mon, 01 Sep 2008 17:40 (GMT+1)
IVDF version:	7.00.06.100 - Mon, 01 Sep 2008 17:40 (GMT+1)

General Method of propagation:
   • Messenger

Aliases:
   • Symantec: W32.Svich
   • Kaspersky: Trojan-Downloader.Win32.AutoIt.aa
   • TrendMicro: WORM_SOHANAD.EI
   • F-Secure: Trojan-Downloader.Win32.AutoIt.aa
   • Sophos: W32/Sohana-Y
   • Panda: W32/Sohanat.BY.worm
   • Eset: Win32/Hakaglan.C
   • Bitdefender: Trojan.Downloader.Autoit.V

Platforms / OS:
   • Windows 98
   • Windows 98 SE
   • Windows NT
   • Windows ME
   • Windows 2000
   • Windows XP
   • Windows 2003

Side effects:
   • Downloads files
   • Lowers security settings
   • Registry modification

Files It copies itself to the following locations:
   • %SYSDIR%\SSCVIIHOST.exe
   • %WINDIR%\SSCVIIHOST.exe
   • %SYSDIR%\blastclnnn.exe

The following files are created:

– Non malicious file:
   • %SYSDIR%\setting.ini

– %WINDIR%\Tasks\At1.job File is a scheduled task that runs the malware at predefined times.
– %SYSDIR%\autorun.ini Further investigation pointed out that this file is malware, too. Detected as: TR/Autorun.A.2

It tries to download some files:

– The location is the following:
   • setting3.**********
At the time of writing this file was not online for further investigation.

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

Registry The following registry key is added in order to run the process after reboot:

– [HKCU\Software\Microsoft\Windows\CurrentVersion\Run]
   • Yahoo Messengger="%SYSDIR%\SSCVIIHOST.exe"

The following registry keys are added in order to load the service after reboot:

– [HKLM\SYSTEM\ControlSet001\Services\Schedule]
   • AtTaskMaxHours=dword:00000000

The following registry keys are changed:

Various Explorer settings:
– [HKCU\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer]
   New value:
   • NofolderOptions=dword:00000001

Disable Regedit and Task Manager:
– [HKCU\Software\Microsoft\Windows\CurrentVersion\Policies\System]
   New value:
   • DisableTaskMgr=dword:00000001
   • DisableRegistryTools=dword:00000001

– [HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon]
   Old value:
   • "Shell"="Explorer.exe"
   New value:
   • Shell="Explorer.exe SSCVIIHOST.exe"

Messenger It is spreading via Messenger. The characteristics are described below:

– Yahoo Messenger

To:
All entries in the contact list.

The received message may look like the following:

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 the following runtime packer:
• UPX

See a brief description here.

Description inserted by Alexandru Dinu on Tue, 09 Sep 2008 14:03 (GMT+1)
Description updated by Alexandru Dinu on Tue, 09 Sep 2008 15:47 (GMT+1)

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