Analysis by: Joachim Suico
ALIASES:

HEUR:Trojan.Script.Generic (Kaspersky); Trojan.Generic (Qihoo-360)

 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

Infection Channel: Spammed via email, Downloaded from the Internet

This Trojan arrives as an attachment to email messages spammed by other malware/grayware or malicious users. It arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

  TECHNICAL DETAILS

File Size: 9,338 bytes
File Type: HTML, HTM
Memory Resident: No
Initial Samples Received Date: 27 Jan 2015

Arrival Details

This Trojan arrives as an attachment to email messages spammed by other malware/grayware or malicious users.

It arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

NOTES:

This Trojan attempts to reconfigure the Domain Name System (DNS) settings of the router used by the affected system. It uses the following IP addresses to guess the router's correct IP address:

  • 192.168.0.1
  • 192.168.1.1
  • 192.168.3.1
  • 192.168.2.1
  • 10.0.0.1
  • 10.1.1.1
  • 10.1.0.1

It uses the following user name to access the router:

  • admin

It uses the following passwords to access the router:

  • admin
  • gvt12345

Once this Trojan successfully accesses the router, it sets the Primary and Secondary DNS servers to the following possibly malicious IP addresses:

  • Primary DNS server - {BLOCKED}.{BLOCKED}.139.248
  • Secondary DNS server - {BLOCKED}.{BLOCKED}.66.183

This malicious routine exposes the affected system to man-in-the-middle (MitM) attacks.

  SOLUTION

Minimum Scan Engine: 9.750
FIRST VSAPI PATTERN FILE: 11.446.02
FIRST VSAPI PATTERN DATE: 29 Jan 2015
VSAPI OPR PATTERN File: 11.447.00
VSAPI OPR PATTERN Date: 30 Jan 2015

Step 1

Before doing any scans, Windows XP, Windows Vista, and Windows 7 users must disable System Restore to allow full scanning of their computers.

Step 2

Note that not all files, folders, and registry keys and entries are installed on your computer during this malware's/spyware's/grayware's execution. This may be due to incomplete installation or other operating system conditions. If you do not find the same files/folders/registry information, please proceed to the next step.

Step 3

Scan your computer with your Trend Micro product to delete files detected as
 HTML_DNSCHA.SM

*Note: 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.