WORM_GAMARUE.H

 Analysis by: Rhena Inocencio

 ALIASES:

Worm:Win32/Gamarue.F (Microsoft), Worm.Win32.VBNA.bamp (Kaspersky)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

 OVERALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW


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

It deletes the initially executed copy of itself.

  TECHNICAL DETAILS

File Size:

86,016 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

15 Jul 2012

Arrival Details

This worm arrives via removable drives.

It 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 and executes them:

  • {All User's Profile}\Local Settings\Temp\ms{random characters}.{extension name}

It injects codes into the following process(es):

  • wuauclt.exe

Autostart Technique

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\policies\
Explorer\Run
{random number} = "{All User's Profile}\Local Settings\Temp\ms{random characters}.{random extension}"

Propagation

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

  • ms{random characters}.{extension name}

Other Details

This worm connects to the following possibly malicious URL:

  • http://{BLOCKED}.{BLOCKED}.84.20/pannel/image.php
  • http://{BLOCKED}.{BLOCKED}.44.162/u/fuckedupshit.exe

It deletes the initially executed copy of itself

NOTES:

Where {extension name} is any of the following:

  • BAT
  • CMD
  • COM
  • EXE
  • PIF
  • SCR

  SOLUTION

Minimum Scan Engine:

9.200

FIRST VSAPI PATTERN FILE:

9.284.03

FIRST VSAPI PATTERN DATE:

25 Jul 2012

VSAPI OPR PATTERN File:

9.285.00

VSAPI OPR PATTERN Date:

26 Jul 2012

Step 1

For Windows XP and Windows Server 2003 users, before doing any scans, please make sure you disable System Restore to allow full scanning of your computer.

Step 2

Scan your computer with your Trend Micro product and note files detected as WORM_GAMARUE.H

Step 3

Restart in Safe Mode

[ Learn More ]

Step 4

Delete this registry value

[ Learn More ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.

  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\policies\Explorer\Run
  • {random number} = "{All User's Profile}\Local Settings\Temp\ms{random characters}.{extension name}"

Step 5

Restart in normal mode and scan your computer with your Trend Micro product for files detected as WORM_GAMARUE.H. If the detected files have already been cleaned, deleted, or quarantined by your Trend Micro product, no further step is required. You may opt to simply delete the quarantined files. Please check this Knowledge Base page for more information.


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