ALIASES:

Trojan:WinNT/Darkshell.C (Microsoft); Trojan.Gen.2 (Symantec); Trojan.Win32.Siscos.jpq (Kaspersky); Backdoor.Win32.Ircbot.gen (v) (Sunbelt); Trojan horse PSW.OnlineGames_r.DR (AVG)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

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

It deletes itself after execution.

  TECHNICAL DETAILS

File Size: 1,067,520 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 05 Feb 2013

Arrival Details

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

Installation

This backdoor drops the following copies of itself into the affected system:

  • %System%\firefox.exe

(Note: %System% is the Windows system folder, which is usually C:\Windows\System32.)

Other System Modifications

This backdoor deletes the following files:

  • 59.txt

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\FireFox
Description = "FireFox Browser Driver"

Other Details

This backdoor connects to the following possibly malicious URL:

  • http://www.{BLOCKED}ya.com/din.htm

It deletes itself after execution.

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine: 9.300

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

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_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\FireFox
    • Description = "FireFox Browser Driver"

Step 3

Scan your computer with your Trend Micro product to delete files detected as BKDR_DARKSHELL.MZX. 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.

Step 4

Restore this file from backup only Microsoft-related files will be restored. If this malware/grayware also deleted files related to programs that are not from Microsoft, please reinstall those programs on you computer again.

  • 59.txt


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