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Virus:DR/Sohanad.BM.157
Date discovered:30/09/2009
Type:Trojan
In the wild:Yes
Reported Infections:Low to medium
Distribution Potential:Low to medium
Damage Potential:Low to medium
Static file:Yes
File size:529.920 Bytes
MD5 checksum:ec80ba08fe2710d8ab5ad280f1b37137
IVDF version:7.01.06.59 - Wednesday, September 30, 2009

 General Aliases:
   •  Mcafee: W32/YahLover.worm
   •  Sophos: W32/SillyFDC-G
   •  Panda: W32/Hakaglan.A.worm
   •  Eset: Win32/Hakaglan.AH
   •  Bitdefender: Trojan.AutoIt.TD


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


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

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



The following file is created:

%WINDIR%\Tasks\At1.job



It tries to download some files:

– The location is the following:
   • http://nhatquanglan2.0catch.com/**********
At the time of writing this file was not online for further investigation.

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

– The location is the following:
   • http://nhatquanglan2.0catch.com/**********
At the time of writing this file was not online for further investigation.

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

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

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



The following registry key is added:

– [HKCU\Software\Microsoft\Windows\CurrentVersion\Policies\System]
   • "DisableRegistryTools"=dword:0x00000001
   • "DisableTaskMgr"=dword:0x00000001



The following registry keys are changed:

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

– [HKLM\SYSTEM\CurrentControlSet\Services\Schedule]
   New value:
   • "AtTaskMaxHours"=dword:0x00000000
   • "NextAtJobId"=dword:0x00000003

– [HKCU\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer]
   New value:
   • "NofolderOptions"=dword:0x00000001

– [HKCU\Software\Microsoft\Windows\CurrentVersion\Internet Settings]
   New value:
   • "GlobalUserOffline"=dword:0x00000000

 Process termination The following process is terminated:
   • taskmgr.exe


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

Description inserted by Petre Galan on Friday, February 5, 2010
Description updated by Petre Galan on Friday, February 5, 2010

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