ALIASES:

Worm:Win32/Autorun.gen!BS (Microsoft); BackDoor-DOQ (McAfee); Downloader (Symantec); Worm.Win32.AutoRun.eav (Kaspersky); Worm.Win32.Socks.bt (fs) (Sunbelt); Backdoor:W32/Agent.DBY (FSecure)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

This worm 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: 270,336 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 25 May 2013

Arrival Details

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

  • %System%\drivers\spools.exe
  • %User Profile%\cftmon.exe

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

Autostart Technique

This worm modifies the following registry entries to ensure it automatic execution at every system startup:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon
Shell = "Explorer.exe"

(Note: The default value data of the said registry entry is Explorer.exe.)

Other System Modifications

This worm deletes the following files:

  • %System Root%\stop
  • %System%\WLCtrl32.dll
  • %System%\drivers\grande48.sys

(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.. %System% is the Windows system folder, which is usually C:\Windows\System32.)

It modifies the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon
UIHost = "logonui.exe"

(Note: The default value data of the said registry entry is {random values}.)

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\Schedule
ImagePath = "%System%\drivers\spools.exe"

(Note: The default value data of the said registry entry is {random values}.)

It deletes the following registry keys:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon\
Notify\WLCtrl32

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Control\SafeBoot\Minimal

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Control\SafeBoot\Network

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run

HKEY_CURRENT_USER\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run

Other Details

This worm connects to the following possibly malicious URL:

  • http://client155.{BLOCKED}-hosting.com/?&v=bf1&s=0

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

Identify and delete files detected as WORM_SOCKS.EJ using either the Startup Disk or Recovery Console

[ Learn More ]

Step 3

Restore these modified registry values

[ Learn More ]

Important:Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this only if you know how to or you can seek your system administrator's help. You may also check out this Microsoft article first before modifying your computer's registry.

  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
    • From: UIHost = "logonui.exe"
      To: UIHost = ""{random values}""
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\Schedule
    • From: ImagePath = "%System%\drivers\spools.exe"
      To: ImagePath = ""{random values}""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
    • From: Shell = "Explorer.exe"
      To: Shell = ""Explorer.exe""

Step 4

Scan your computer with your Trend Micro product to delete files detected as WORM_SOCKS.EJ. 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 5

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%\stop
  • %System%\WLCtrl32.dll
  • %System%\drivers\grande48.sys

Step 6

Restore these deleted registry keys/values from backup

*Note: Only Microsoft-related keys/values will be restored. If the malware/grayware also deleted registry keys/values related to programs that are not from Microsoft, please reinstall those programs on your computer.

  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\Notify
    • WLCtrl32
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\SafeBoot
    • Minimal
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\SafeBoot
    • Network
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001
    • Services
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion
    • Run
  • In HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion
    • Run


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