TROJ_QHOST.CLM

October 09, 2012
 Analysis by: Cris Nowell Pantanilla
 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.

As of this writing, the said sites are inaccessible.

It modifies the affected system's HOSTS files. This prevents users from accessing certain websites.

  TECHNICAL DETAILS

File Size:

103,424 bytes

Memory Resident:

Yes

Initial Samples Received Date:

27 Sep 2011

Payload:

Downloads files

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.

Download Routine

This Trojan accesses the following websites to download files:

  • imagehut4.cn

As of this writing, the said sites are inaccessible.

HOSTS File Modification

This Trojan adds the following strings to the Windows HOSTS file:

  • 127.0.0.1 thepiratebay.org
  • 127.0.0.1 www.thepiratebay.org
  • 127.0.0.1 mininova.org
  • 127.0.0.1 www.mininova.org
  • 127.0.0.1 forum.mininova.org
  • 127.0.0.1 blog.mininova.org
  • 127.0.0.1 suprbay.org
  • 127.0.0.1 www.suprbay.org

NOTES:
It perform the command ipconfig /flushdns to clear the DNS cache of the affected system. This ensures that the user is unable to access the sites added in the host file (if the user already have the IP addresses for the sites).

  SOLUTION

Minimum Scan Engine:

9.200

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 terminate files detected as TROJ_QHOST.CLM

[ Learn More ]
  1. If the detected file is displayed in either Windows Task Manager or Process Explorer but you cannot delete it, restart your computer in safe mode. To do this, refer to this link for the complete steps.
  2. If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.

Step 3

Remove these strings added by the malware/grayware/spyware in the HOSTS file

[ Learn More ]
    • 127.0.0.1 thepiratebay.org
    • 127.0.0.1 www.thepiratebay.org
    • 127.0.0.1 mininova.org
    • 127.0.0.1 www.mininova.org
    • 127.0.0.1 forum.mininova.org
    • 127.0.0.1 blog.mininova.org
    • 127.0.0.1 suprbay.org
    • 127.0.0.1 www.suprbay.org
"

Step 4

Scan your computer with your Trend Micro product to delete files detected as TROJ_QHOST.CLM. 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.


Did this description help? Tell us how we did.