BKDR_FAKEDOBE.JB


 PLATFORM:

Windows 2000, Windows Server 2003, Windows XP (32-bit, 64-bit), Windows Vista (32-bit, 64-bit), Windows 7 (32-bit, 64-bit)

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Downloaded from the Internet, Dropped by other malware

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 executes commands from a remote malicious user, effectively compromising the affected system.

  TECHNICAL DETAILS

File Size:

2,310,144 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

01 Jun 2013

Payload:

Compromises system security

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 and executes them:

  • %Application Data%\Win\WinUpdate.exe

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

It drops the following files:

  • %Application Data%\log - log file of activities

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

It drops and executes the following files:

  • %User Temp%\{RANDOM}.bat

(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, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista and 7.)

It drops the following copies of itself into the affected system:

  • %Application Data%\S6TD4WUQZL.exe

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

It creates the following folders:

  • %Application Data%\Win

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

Autostart Technique

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
Windows Update = "%Application Data%\Win\WinUpdate.exe"

Other System Modifications

This backdoor adds the following registry keys:

HKEY_CURRENT_USER\Software\VB and VBA Program Settings

HKEY_CURRENT_USER\Software\VB and VBA Program Settings\
INSTALL

HKEY_CURRENT_USER\Software\VB and VBA Program Settings\
INSTALL\DATE

HKEY_CURRENT_USER\Software\VB and VBA Program Settings\
SrvID

HKEY_CURRENT_USER\Software\VB and VBA Program Settings\
SrvID\ID

It adds the following registry entries:

HKEY_CURRENT_USER\Software\VB and VBA Program Settings\
INSTALL\DATE
98UJ1H0LYI = "{date of first execution}"

HKEY_CURRENT_USER\Software\VB and VBA Program Settings\
SrvID\ID
98UJ1H0LYI = "PM"

It creates the following registry entry(ies) to bypass Windows Firewall:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\AuthorizedApplications\List
%Application Data%\Win\WinUpdate.exe = "%Application Data%\Win\WinUpdate.exe:*:Enabled:Windows Messanger"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\AuthorizedApplications\List
%Application Data%\S6TD4WUQZL.exe = "%Application Data%\S6TD4WUQZL.exe:*:Enabled:Windows Messanger"

Backdoor Routine

This backdoor executes the following commands from a remote malicious user:

  • Open/Close CD-Rom
  • On/Off Monitor
  • Shutdown/Restart machine
  • Increase/Decrease/Mute Volume
  • Set Screensaver
  • Key logger
  • Capture screenshot/video/sound
  • Disable clipboard
  • Set Cursor
  • Swap Mouse Button
  • Start/Terminate Browser
  • Download File
  • Get Logical Drives information
  • Perform Remote Shell

It connects to the following URL(s) to send and receive commands from a remote malicious user:

  • {BLOCKED}.{BLOCKED}.212.110
  • {BLOCKED}.{BLOCKED}.77.13

  SOLUTION

Minimum Scan Engine:

9.300

FIRST VSAPI PATTERN FILE:

9.954.06

FIRST VSAPI PATTERN DATE:

02 Jun 2013

VSAPI OPR PATTERN File:

9.955.00

VSAPI OPR PATTERN Date:

02 Jun 2013

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 key

[ 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_CURRENT_USER\Software
    • VB and VBA Program Settings

Step 4

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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • Windows Update = "%Application Data%\Win\WinUpdate.exe"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\AuthorizedApplications\List
    • %Application Data%\Win\WinUpdate.exe = "%Application Data%\Win\WinUpdate.exe:*:Enabled:Windows Messanger"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\AuthorizedApplications\List
    • %Application Data%\S6TD4WUQZL.exe = "%Application Data%\S6TD4WUQZL.exe:*:Enabled:Windows Messanger"

Step 5

Search and delete these folders

[ 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.
  • %Application Data%\Win

Step 6

Search and delete this file

[ Learn More ]
There may be some 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%\{RANDOM}.bat

Step 7

Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_FAKEDOBE.JB. 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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