Analysis by: rolandde
ALIASES:

Trojan:Win32/Dynamer!dtc (Microsoft)

 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 may be downloaded by other malware/grayware from remote sites. It may be dropped by other malware.

It uses common file icons to trick a user into thinking that the files are legitimate.

  TECHNICAL DETAILS

File Size: 86,016 bytes
Memory Resident: No
Initial Samples Received Date: 06 Dec 2011
Payload: Connects to URLs/IPs

Arrival Details

This Trojan may be downloaded by the following malware/grayware from remote sites:

  • http://www.{BLOCKED}1.pe.kr/a/download/exe/ver53/uninstall_v53.exe

It may be dropped by other malware.

Installation

This Trojan uses common file icons to trick a user into thinking that the files are legitimate.

NOTES:

It is a component malware that is used to uninstall other malware components in the system.

It may be used to delete malware components and unregister malware registry entries under the following registry keys:

  • SOFTWARE\Microsoft\Windows\CurrentVersion\Run
  • SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall

It then sends an uninstall report to the following site:

  • http://www.{BLOCKED}over.net/a/asp/deleteall.php?uncode={parameter}

  SOLUTION

Minimum Scan Engine: 9.200
FIRST VSAPI PATTERN FILE: 8.630.10
FIRST VSAPI PATTERN DATE: 06 Dec 2011
VSAPI OPR PATTERN File: 8.631.00
VSAPI OPR PATTERN Date: 06 Dec 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

Scan your computer with your Trend Micro product to delete files detected as TROJ_VBUNST.A. 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:

Recommendations

1. Enable firewall to protect against threats.

  • http://esupport.trendmicro.com/3/How-do-I-enable-or-disable-the-Personal-Firewall-of-Trend-Micr-EN-1038273.aspx

2. Avoid accessing the listed malicious URLs to prevent possible re-infection.

3. Monitor network connections for any suspicious connection or connectivity.

4. Regularly update list of sites that are trusted.

5. Clear browser cache and delete cookies regularly.

6. Delete files in the %User Temp% folder.


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