Virus:Worm/Autorun.nuz
Date discovered:30/10/2008
Type:Worm
In the wild:Yes
Reported Infections:Low to medium
Distribution Potential:Low
Damage Potential:Medium
Static file:No
IVDF version:7.01.00.18 - Thursday, October 30, 2008

 General Method of propagation:
   • No own spreading routine


Aliases:
   •  Symantec: Trojan.Virantix.C
   •  Sophos: Mal/EncPk-EQ
   •  Grisoft: Dropper.Bravix.K
   •  Eset: Win32/TrojanDownloader.FakeAlert.PL.Gen trojan
   •  Bitdefender: Trojan.Fakealert.ALU


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 The following files are created:

– %SYSDIR%\brastk.exe Furthermore it gets executed after it was fully created. Further investigation pointed out that this file is malware, too. Detected as: Worm/Autorun.nuz

– %SYSDIR%\dllcache\figaro.sys Further investigation pointed out that this file is malware, too. Detected as: TR/Rootkit.Gen

– %SYSDIR%\dllcache\beep.sys Further investigation pointed out that this file is malware, too. Detected as: TR/Rootkit.Gen

– %SYSDIR%\drivers\beep.sys Further investigation pointed out that this file is malware, too. Detected as: TR/Rootkit.Gen

– %WINDIR%\delself.bat This batch file is used to delete a file.

 Registry The following registry keys are added in order to run the processes after reboot:

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

– [HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run]
   • brastk="%SYSDIR%\brastk.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 Friday, November 7, 2008
Description updated by Thomas Wegele on Friday, November 7, 2008

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