Analysis by: Sabrina Lei Sioting
ALIASES:

Trojan:Win32/Demtranc.C (Microsoft); Backdoor.Win32.Agent.arag (Kaspersky); Backdoor.Specfix.B (Symantec); BackDoor-EKF (McAfee); Trojan.Win32.Demtranc (Ikarus)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted: Yes

  • 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.

  TECHNICAL DETAILS

File Size: 124,928 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 25 Aug 2010

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 file(s)/component(s):

  • %User Temp%\wuweb.exe
  • %User Startup%\msproof.exe

(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003.. %User Startup% is the current user's Startup folder, which is usually C:\Windows\Profiles\{user name}\Start Menu\Programs\Startup on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Start Menu\Programs\Startup on Windows NT, and C:\Documents and Settings\{User name}\Start Menu\Programs\Startup.)

It drops the following non-malicious file:

  • %User Temp%\{malware name}.pdf

(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003.)

Other Details

This backdoor connects to the following possibly malicious URL:

  • http://{BLOCKED}1.201/{random characters}d.jsp?{random characters}

  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

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.
  • %User Temp%\{malware name}.pdf
  • %User Temp%\wuweb.exe
  • %User Startup%\msproof.exe

Step 3

Scan your computer with your Trend Micro product to delete files detected as BKDR_PROXY.SMS. 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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