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TROJ_VUNDO.SMIB

August 06, 2011
 Analysis by: Cris 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.

As of this writing, the said sites are inaccessible.

It connects to certain websites to send and receive information. It deletes the initially executed copy of itself.

  TECHNICAL DETAILS

File Size:

Varies

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

19 Jul 2011

Payload:

Connects to URLs/IPs

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 component file(s):

  • %System%\{Random}.dll - also detected as TROJ_VUNDO.SMIB

(Note: %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows XP and Server 2003.)

It injects threads into the following normal process(es):

  • EXPLORER.EXE

Other System Modifications

This Trojan adds the following registry entries:

HKEY_CLASSES_ROOT\CLSID\{4CB8F4B4-5F66-4D9E-BC3B-184596A58824}\
InprocServer32
(Default) = "%System%\{random}.dll"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings
GlobalUserOffline = "0"

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{4CB8F4B4-5F66-4D9E-BC3B-184596A58824}

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Explorer\
ShellExecuteHooks
{4CB8F4B4-5F66-4D9E-BC3B-184596A58824} =

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon\
Notify\{Random}
Asynchronous = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon\
Notify\{Random}
DllName = "{Random}.dll"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon\
Notify\{Random}
Impersonate = "0"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon\
Notify\{Random}
Logon = "Logon"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon\
Notify\{Random}
Logoff = "Logoff"

Download Routine

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

  • http://{BLOCKED}.235.70/443

As of this writing, the said sites are inaccessible.

Other Details

This Trojan connects to the following website to send and receive information:

  • http://{BLOCKED}.103.60/go//?cmp=vmtek_update&lid=run&uid={data}&guid={data}

It drops the following file(s)/component(s):

  • %User Temp%\removalfile.bat

(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003.)

It deletes the initially executed copy of itself

  SOLUTION

Minimum Scan Engine:

8.900

FIRST VSAPI PATTERN FILE:

8.298.08

FIRST VSAPI PATTERN DATE:

19 Jul 2011

Step 1

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

Step 2

Restart in Safe Mode

[ Learn More ]

Step 3

Delete this registry key

[ 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_CLASSES_ROOT\CLSID
    • {4CB8F4B4-5F66-4D9E-BC3B-184596A58824}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID
    • {4CB8F4B4-5F66-4D9E-BC3B-184596A58824}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\ShellExecuteHooks
    • {4CB8F4B4-5F66-4D9E-BC3B-184596A58824}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\Notify\
    • {Random}

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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings
    • GlobalUserOffline = 0

Step 5

Search and delete this file

[ Learn More ]

There may be some component files that are hidden. Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden files and folders in the search result.
  • %User Temp%\removalfile.bat

Step 6

Scan your computer with your Trend Micro product to delete files detected as TROJ_VUNDO.SMIB 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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