TROJ_SHIZ.SMF

 Analysis by: Karl Dominguez

 PLATFORM:

Windows 2000, XP, 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 may be downloaded by other malware/grayware/spyware from remote sites. It may be unknowingly downloaded by a user while visiting malicious websites. However, as of this writing, the said sites are inaccessible.

  TECHNICAL DETAILS

File Size:

Varies

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

02 Oct 2010

Payload:

Downloads files

Arrival Details

This Trojan may be downloaded by other malware/grayware/spyware from remote sites.

It may be unknowingly downloaded by a user while visiting malicious websites.

However, as of this writing, the said sites are inaccessible.

Installation

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

  • \\?\globalroot\systemroot\system32\{random characters}.exe
  • %System%\{random characters}.exe

(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 stays memory-resident by injecting codes into the following processes:

  • svchost.exe

Autostart Technique

This Trojan modifies the following registry entry(ies) to enable its automatic execution at every system startup:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon
Userinit = %System%\userinit.exe,%System%\33e7b51.exe,

(Note: The default value data of the said registry entry is %System%\userinit.exe,.)

Other System Modifications

This Trojan also creates the following registry entry(ies) as part of its installation routine:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft
m1131 =

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft
m1132 =

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft
m1133 =

Download Routine

This Trojan connects to the following URL(s) to download its configuration file:

  • http://{BLOCKED}rres.com/knock.php?n={volume information}&s=seller-01

Other Details

This Trojan does the following:

  • It temporarily saves the downloaded configuration file as %User Temp%\nt{random numbers}.tmp. This configuration file is then deleted by the malware after saving the contents in the following registry:
    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft
    m1131
    m1132
    m1133.
    Based on the codes, the configuration file contains additional URL(s) where the malware may connects to, possibly to download and execute other possible malicious file. The downloaded file is saved as %User Temp%\nt{random numbers}.tmp.exe.

(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.)

  SOLUTION

Minimum Scan Engine:

8.900

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

Identify and delete files detected as TROJ_SHIZ.SMF using either the Startup Disk or Recovery Console

[ Learn More ]

Step 3

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\Windows NT\CurrentVersion\Winlogon
    • From: Userinit = %System%\userinit.exe,%System%\{malware file name}.exe,
      To: Userinit = %System%\userinit.exe,

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
    • m1131
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft
    • m1132
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft
    • m1133

Step 5

Search and delete these files

[ 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%\nt{random numbers}.tmp.exe

Step 6

Scan your computer with your Trend Micro product to delete files detected as TROJ_SHIZ.SMF. 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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