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WORM_VOBFUS.SMCX
Malware type: Worm
Destructive: No
Platform: Windows 2000, Windows XP, Windows Server 2003
In the wild: Yes

Overview


This worm arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

It modifies registry entries to hide files with System and Read-only attributes.

It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.

Technical Details

File size: 176,128 bytes
File type: EXE
Memory resident: Yes
Initial samples received date: 23 Nov 2012

Arrival Details

This worm arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

Installation

This worm drops the following copies of itself into the affected system:

  • %UserProfile%\{random}.exe
  • %UserProfile%\Passwords.exe
  • %UserProfile%\Porn.exe
  • %UserProfile%\Secret.exe
  • %UserProfile%\Sexy.exe

Autostart Technique

This worm adds the following registry entries to enable its automatic execution at every system startup:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
{random} = "%User Profile%\{random}.exe /r"

Other System Modifications

This worm adds the following registry keys:

HKEY_LOCAL_MACHINE\SOFTWARE\Policies\
Microsoft\Windows\WindowsUpdate\
AU

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Policies\
Microsoft\Windows\WindowsUpdate\
AU
NoAutoUpdate = "00000001"

It modifies the following registry entries to hide files with System and Read-only attributes:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
ShowSupperHidden = "00000001"

(Note: The default value data of the said registry entry is 00000000.)

Propagation

This worm drops the following copy(ies) of itself in all removable drives:

  • {Drive Letter}\Porn.exe
  • {Drive Letter}\Secret.exe
  • {Drive Letter}\Sexy.exe
  • {Drive Letter}\{random}.exe
  • {Drive Letter}\Passwords.exe

It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.

The said .INF file contains the following strings:

[autorun]
open={RANDOM}.eXE
AcTiOn=23199
usEAutopLAy=1

Other Details

This worm connects to the following possibly malicious URL:

  • {BLOCKED}.{BLOCKED}dater.net

Analysis By: Rika Joi Gregorio

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