TROJ_TRACUR.JWE

October 09, 2012
 Analysis by: Jasen Sumalapao
 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Downloaded from the Internet

This Trojan may arrive bundled with malware packages as a malware component. 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 uses a file name similar to a legitimate file to pass as a legitimate file.

It exports functions used by other malware. It requires its main component to successfully perform its intended routine.

  TECHNICAL DETAILS

File Size:

393,216 bytes

File Type:

DLL

Memory Resident:

Yes

Initial Samples Received Date:

28 Jun 2012

Arrival Details

This Trojan may arrive bundled with malware packages as a malware component.

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 Trojan drops the following copies of itself into the affected system and executes them:

  • %User Profile%\Local Settings\Application Data\{Random Folder}\{Malware Filename}.dll

(Note: %User Profile% is the current user's profile folder, which is usually C:\Windows\Profiles\{user name} on Windows 98 and ME, C:\WINNT\Profiles\{user name} on Windows NT, and C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003.)

It adds the following mutexes to ensure that only one of its copies runs at any one time:

  • {random characters}

It uses a file name similar to a legitimate file to pass as a legitimate file.

Autostart Technique

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
{Random Folder} = "rundll32.exe "%User Profile%\Local Settings\Application Data\{Random Folder}\{malware filename}.dll",CreateInstance"

Other System Modifications

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

HKEY_CURRENT_USER\Software\{random characters}\
CLSID
{default} = {random CLSID}

Other Details

This Trojan exports functions used by other malware.

It requires its main component to successfully perform its intended routine.

NOTES:

The random characters in the following registry entry is the same as the created mutex:

HKEY_CURRENT_USER\Software\{random characters}\CLSID
{default} = {random CLSID}

Example:

Mutex: Nixcllssck

The created registry would be:

HKEY_CURRENT_USER\Software\Nixcllssck\CLSID
{default} = {random CLSID}

  SOLUTION

Minimum Scan Engine:

9.200

FIRST VSAPI PATTERN FILE:

9.222.04

FIRST VSAPI PATTERN DATE:

28 Jun 2012

VSAPI OPR PATTERN File:

9.223.00

VSAPI OPR PATTERN Date:

29 Jun 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

Restart in Safe Mode

[ Learn More ]

Step 3

Search and delete the file detected as TROJ_TRACUR.JWE

*Note: Some component files may be 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.

To manually delete a malware/grayware file from the affected system:

  1. Right-click Start then click Search....
  2. In the Named input box, type the name of the file that was detected earlier.
  3. In the Look In drop-down list, select My Computer then press Enter.
  4. Once located, select the file then press SHIFT+DELETE to delete it.

Step 4

Delete the registry entry with an unknown data 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\Run
    • {Random Folder} = "rundll32.exe "%User Profile%\Local Settings\Application Data\{Random Folder}\{malware filename}.dll",CreateInstance"

Step 5

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

NOTES:

The created registry key HKEY_CURRENT_USER\Software\{random characters}\CLSID cannot be identified by the user since there are no reference values in the created key. The only way it can be identified is by comparing the present keys with a backup if the users have one or identify the created Mutex as reference. Note that the key need not to be deleted since it won't cause the user system any harm.


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