Analysis by: Sabrina Lei Sioting
 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

  TECHNICAL DETAILS

File Size: Varies
File Type: DOC
Memory Resident: No
Initial Samples Received Date: 04 Feb 2011

Installation

This Trojan drops the following files:

  • %temp%\set.jtd - normal ichitaro file
  • %temp%\ews.exe - detected by Trend Micro as TROJ_DROPPER.BIY

Other Details

This Trojan does the following:

  • Executes the normal Ichitaro file using the following commandline:
    • cmd /c start taro18 "%temp%\set.jtd"
  • Executes the malicious file using the following commandline:
    • "%temp%\ews.exe" or "%temp%\ews.exe" -start

  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

Remove malware files dropped/downloaded by TROJ_TARO.SMM

    TROJ_DROPPER.BIY

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.  %temp%\ews.exe

Step 4

Scan your computer with your Trend Micro product to delete files detected as TROJ_TARO.SMM. 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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