TROJ_AGENT.EOA

 Analysis by: Sabrina Lei Sioting

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: No

  • 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 may be dropped by other malware.

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

  TECHNICAL DETAILS

File Size:

16,896 bytes

Memory Resident:

Yes

Initial Samples Received Date:

22 Sep 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.

It may be dropped by other malware.

Dropping Routine

This Trojan drops the following files:

  • %System%\trkwks.dll

(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.)

Other Details

This Trojan connects to the following possibly malicious URL:

  • www.{BLOCKED}air.com

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

NOTES:
It saves the original %System\trkwks.dll to %System%\wtrkwks.dll.

  SOLUTION

Minimum Scan Engine:

9.200

FIRST VSAPI PATTERN FILE:

8.444.01

FIRST VSAPI PATTERN DATE:

22 Sep 2011

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 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.
  • %System%\trkwks.dll

Step 4

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

Step 5

Restoring a File to its Original Location

  1. Click Start>Run.
  2. In the text box, type the following:
    command /c copy
    %windir%\system32\wtrkwks.dll %windir%\system32\trkwks.dll
  3. Press Enter.


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