Analysis by: Kathleen Notario
 PLATFORM:

Windows 98, ME, NT, 2000, XP, Server 2003

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

Trend Micro has received multiple samples of this malware from a malicious domain source that have infected many clients. These indicate that this malware poses a high risk to users due to the increased possibility of infection.

To get a one-glance comprehensive view of the behavior of this Trojan, refer to the Threat Diagram shown below.

This Trojan executes downloaded files whose malicious routines are exhibited by the affected system.

  TECHNICAL DETAILS

File Size: 20,480 bytes
File Type: PE
Memory Resident: Yes
Initial Samples Received Date: 18 Jan 2010
Payload: Downloads files

Arrival Details

This Trojan may be downloaded from the following remote sites:

  • http://{BLOCKED}.in

Autostart Technique

This Trojan drops the following files:

  • %All Users%\Favorites\_favdata.dat

Other System Modifications

This Trojan adds the following registry entries:

HKEY_CURRENT_USER\Printers\Connections
affid = "262"

HKEY_CURRENT_USER\Printers\Connections
subid = "new"

Download Routine

This Trojan accesses the following websites to download files:

  • http://{BLOCKED}c-Update.com/ms05/ad
  • http://www.{BLOCKED}curityscan.com/ms05/ad
  • http://www.{BLOCKED}sim.com/ms05/ad

Trend Micro detects the dowloaded file as:

  • TROJ_FAKEAV.CLC

It executes downloaded files :

    whose malicious routines are exhibited by the affected system.

      SOLUTION

    Minimum Scan Engine: 8.900
    VSAPI OPR PATTERN File: 6.781.00
    VSAPI OPR PATTERN Date: 18 Jan 2010

    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_TDSS.ANO

    Step 3

    Delete this registry value

    [ Learn More ]

    Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.

    • In HKEY_CURRENT_USER\Printers\Connections
      • affid = 262
    • In HKEY_CURRENT_USER\Printers\Connections
      • subid = new

    Step 4

    Search and delete these files

    [ 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.
    •  %All Users%\Favorites\_favdata.dat

    Step 5

    Scan your computer with your Trend Micro product to delete files detected as TROJ_TDSS.ANO. 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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