Analysis by: Cris Nowell Pantanilla
 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

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

It executes the downloaded files. As a result, malicious routines of the downloaded files are exhibited on the affected system.

  TECHNICAL DETAILS

File Size: 88,948 bytes
File Type: PE
Memory Resident: Yes
Initial Samples Received Date: 24 Jan 2011

Arrival Details

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

  • %Windows%\mc152.exe

(Note: %Windows% is the Windows folder, which is usually C:\Windows.)

Autostart Technique

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
{random} = %WINDOWS%\mc152.exe

Other System Modifications

This Trojan adds the following registry entries as part of its installation routine:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\WindowsUpdate\
Auto Update
NoAutoUpdate = 1

HKEY_LOCAL_MACHINE\SOFTWARE\Policies\
Microsoft\Windows Defender
DisableAntiSpyware = 1

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\policies\
Explorer
NoAutoUpdate = 1

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\policies\
Explorer
NoWindowsUpdate = 1

It modifies the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center
UpdatesDisableNotify = 1

(Note: The default value data of the said registry entry is 0.)

Download Routine

This Trojan connects to the following website(s) to download and execute a malicious file:

  • http://{BLOCKED}ick.ru/.7ot4ck/?getexe=loader.exe - WORM_KOOBFACE.AN

It then executes the downloaded files. As a result, malicious routines of the downloaded files are exhibited on the affected system.

  SOLUTION

Minimum Scan Engine: 8.900
VSAPI PATTERN File: 7.788.07
VSAPI PATTERN Date: 24 Jan 2011
VSAPI PATTERN Date: 1/24/2011 12:00:00 AM

Step 1

Scan your computer with your Trend Micro product and note files detected as TROJ_MALAGNT.GL

Step 2

Restart in Safe Mode

[ Learn More ]

Step 3

Remove the malware/grayware file dropped/downloaded by TROJ_MALAGNT.GL

    • WORM_KOOBFACE.AN

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.

 
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • {random} = %WINDOWS%\mc152.exe
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\WindowsUpdate\Auto Update
    • NoAutoUpdate = 1
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows Defender
    • DisableAntiSpyware = 1
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\policies\Explorer
    • NoAutoUpdate = 1
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\policies\Explorer
    • NoWindowsUpdate = 1

Step 5

Restore this modified 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.

  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center 
    • From: UpdatesDisableNotify = 1
      To: UpdatesDisableNotify = 0

Step 6

Search and delete the file detected as TROJ_MALAGNT.GL

[ Learn More ]
Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden files in the search result.

Step 7

Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_MALAGNT.GL. 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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