ALIASES:

Worm:Win32/Sfone.A (Microsoft); W32/Generic.worm.f (McAfee); W32.SillyWNSE (Symantec); Worm.Win32.Agent.cp (Kaspersky); Worm.Win32.Agent.cp (v) (Sunbelt); Worm.Generic.337381 (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: 1,402,969 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 07 Nov 2011

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 creates the following folders:

  • %User Profile%\Microsoft\Dr Watson

(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.)

Autostart Technique

This worm adds the following registry entries to enable its automatic execution at every system startup:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
mssrv32 = "%Windows%\mssrv.exe"

Other System Modifications

This worm modifies the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
DrWatson
NumberOfCrashes = "1"

(Note: The default value data of the said registry entry is 0.)

It deletes the following registry keys:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
PCHealth\ErrorReporting\DW

Dropping Routine

This worm drops the following files:

  • %Windows%\mssrv.exe
  • %User Temp%\norwegian bukkake fucking several models legs .avi.exe
  • %Temporary Internet Files%\brasilian action big .zip.exe
  • %User Profile%\Templates\malaysia sperm masturbation boobs swallow (Tatjana).rar.exe
  • %User Profile%\Dr Watson\drwtsn32.log
  • %User Profile%\Dr Watson\user.dmp

(Note: %Windows% is the Windows folder, which is usually C:\Windows.. %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, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista and 7.. %Temporary Internet Files% is the Temporary Internet Files folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temporary Internet Files on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Local\Microsoft\Windows\Temporary Internet Files on Windows Vista and 7.. %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.)

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

Restart in Safe Mode

[ Learn More ]

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_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • mssrv32 = "%Windows%\mssrv.exe"

Step 4

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\DrWatson
    • From: NumberOfCrashes = "1"
      To: NumberOfCrashes = "0"

Step 5

Search and delete this folder

[ Learn More ]
Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden folders in the search result.
  • %User Profile%\Microsoft\Dr Watson

Step 6

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.
  • %Windows%\mssrv.exe
  • %User Temp%\norwegian bukkake fucking several models legs .avi.exe
  • %Temporary Internet Files%\brasilian action big .zip.exe
  • %User Profile%\Templates\malaysia sperm masturbation boobs swallow (Tatjana).rar.exe
  • %User Profile%\Dr Watson\drwtsn32.log
  • %User Profile%\Dr Watson\user.dmp

Step 7

Restart in normal mode and scan your computer with your Trend Micro product for files detected as WORM_AGENT.JM. 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 8

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\PCHealth\ErrorReporting
    • DW


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