ALIASES:

Backdoor:Win32/Simbot.gen (Microsoft); Generic Downloader.x!fwl (McAfee); Downloader (Symantec); Trojan-Downloader.Win32.Rubinurd.b (Kaspersky); Trojan.Win32.Generic!BT (Sunbelt); Gen:Variant.Downloader.19 (FSecure)

 PLATFORM:

Windows 2000, Windows, XP, Windows Server 2003

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted:

  • 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.

  TECHNICAL DETAILS

File Size: 32,768 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 15 Dec 2011

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.

Installation

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

  • {malware path and file name}.tmp1

Other System Modifications

This Trojan deletes the following files:

  • %System Root%\a.bat

(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)

Dropping Routine

This Trojan drops the following files:

  • %User Profile%\Application Data\Microsoft
  • %User Profile%\Microsoft\Crypto
  • %User Profile%\Crypto\RSA
  • %User Profile%\RSA\S-1-5-21-4025279379-4087772427-2915903831-500
  • a.bat

(Note: %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista and 7.)

Other Details

This Trojan connects to the following possibly malicious URL:

  • http://{BLOCKED}.29.142:443/conxq.php?id=0065961161679F1224
  • http://{BLOCKED}.29.142:80/conxq.php?id=0111911161679F1224
  • http://{BLOCKED}.29.142:47/conxq.php?id=0113911161679F1224
  • http://{BLOCKED}51.49:443/conxq.php?id=0147361161679F1224
  • http://{BLOCKED}51.49:79/conxq.php?id=0211361161679F1224

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine: 9.200

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

Search and delete these components

[ Learn More ]
There may be some components 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.
  • %User Profile%\Application Data\Microsoft
  • %User Profile%\Microsoft\Crypto
  • %User Profile%\Crypto\RSA
  • %User Profile%\RSA\S-1-5-21-4025279379-4087772427-2915903831-500
  • a.bat

Step 3

Scan your computer with your Trend Micro product to delete files detected as TROJ_DLOADE.SMJ. 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. %System Root%\a.bat


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