VBS/Yuyun.A - VBS script virus

See also

Summary

Full description

Statistics

Virus:	VBS/Yuyun.A
Date discovered:	20/01/2009
Type:	Worm
In the wild:	Yes
Reported Infections:	Low to medium
Distribution Potential:	Low to medium
Damage Potential:	Low to medium
Static file:	No
File size:	~8.000 Bytes
IVDF version:	7.01.01.150 - Tue, 20 Jan 2009 17:43 (GMT+1)

General Method of propagation:
   • Mapped network drives

Aliases:
   • Mcafee: VBS/Autorun.worm.zo
   • Kaspersky: Trojan.JS.Agent.jp
   • F-Secure: Trojan.JS.Agent.jp
   • Sophos: VBS/AutoRun-UC
   • Eset: VBS/AutoRun.BQ
   • Bitdefender: Worm.VBS.AO

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

Side effects:
   • Access to floppy disk
   • Drops files
   • Registry modification

Files It copies itself to the following locations:
   • %all directories%\Thumbs.db
   • %home%\My Documents\database.mdb
   • %WINDIR%\:Microsoft Office Update for Windows XP.sys

The following files are created:

– Non malicious files:
   • %all directories%\New Folder.lnk
   • %all directories%\Microsoft.lnk
   • %all directories%\%all subdirectories%.lnk

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

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

– HKCU\Software\Microsoft\Windows\CurrentVersion\Run\Explorer
   • Wscript.exe //e:VBScript "%home%\My Documents\database.mdb"

– HKLM\Software\Microsoft\Windows\CurrentVersion\Run\WinUpdate
   • Wscript.exe //e:VBScript "%WINDIR%\:Microsoft Office Update for Windows XP.sys"

The value of the following registry key is removed:

– HKCR\lnkfile
   • IsShortcut

The following registry key is changed:

– HKCU\Software\Microsoft\Windows\CurrentVersion\Policies\System
   New value:
   • DisableRegistrytools = 1

See a brief description here.

Description inserted by Andrei Gherman on Mon, 26 Jan 2009 09:05 (GMT+1)
Description updated by Andrei Gherman on Mon, 26 Jan 2009 09:24 (GMT+1)

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