Virus:TR/Drop.Agent.nnu
Date discovered:16/12/2008
Type:Trojan
Subtype:Dropper
In the wild:Yes
Reported Infections:Low
Distribution Potential:Low
Damage Potential:Medium
Static file:Yes
File size:155.221 Bytes
MD5 checksum:18afd000f7d38503b52bd706771cb79e
IVDF version:7.01.00.238 - Tuesday, December 16, 2008

 General Method of propagation:
   • No own spreading routine


Aliases:
   •  Symantec: Trojan.Pandex
   •  Grisoft: Dropper.Small.AGG
   •  Bitdefender: Packer.Malware.NSAnti.1


Platforms / OS:
   • Windows 95
   • Windows 98
   • Windows 98 SE
   • Windows NT
   • Windows ME
   • Windows 2000
   • Windows XP
   • Windows 2003


Side effects:
   • Drops malicious files
   • Registry modification

 Files It copies itself to the following location:
   • %SYSDIR%\zhido.exe



It deletes the initially executed copy of itself.



The following files are created:

– %SYSDIR%\cao220.dll Further investigation pointed out that this file is malware, too. Detected as: TR/Crypt.XPACK.Gen

– %SYSDIR%\cao110.dll Further investigation pointed out that this file is malware, too. Detected as: TR/PSW.OnLineGa.dct

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

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

 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.

Description inserted by Thomas Wegele on Tuesday, December 16, 2008
Description updated by Thomas Wegele on Tuesday, December 16, 2008

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