Analysis by: Adrian Cofreros
 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:
 INFORMATION EXPOSURE:

  • 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. It connects to a website to send and receive information.

It steals certain information from the system and/or the user.

It deletes itself after execution.

  TECHNICAL DETAILS

File Size: 438,272 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 25 Feb 2014
Payload: Compromises system security, Steals information, Connects to URLs/IPs

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):

  • %Application Data%\{username}-wchelper.dll
  • %User Temp%\{username}{number}
  • %Application Data%\DC0C021C\{date}
  • %Application Data%\DC0C021C\ak.tmp

(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.. %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:

  • %System Root%\directory\CyberGate\install\server.exe

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

It creates the following folders:

  • %System Root%\directory - including this subfolder path(\CyberGate\install)

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

Autostart Technique

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
HKLM = "%System Root%\directory\CyberGate\install\server.exe"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
HKCU = "%System Root%\directory\CyberGate\install\server.exe "

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\policies\
Explorer\Run
Policies = "%System Root%\directory\CyberGate\install\server.exe"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Explorer\Run
Policies = "%System Root%\directory\CyberGate\install\server.exe"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Active Setup\Installed Components\{GUID}
StubPath = "%System Root%\directory\CyberGate\install\server.exe Restart"

Other System Modifications

This backdoor adds the following registry keys:

HKEY_CURRENT_USER\Software\remote

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Active Setup\Installed Components\{GUID}

It adds the following registry entries:

HKEY_CURRENT_USER\Software\remote
FirstExecution = "{date of execution} -- {time}"

HKEY_CURRENT_USER\Software\remote
NewIdentification = "remote"

HKEY_CURRENT_USER\Software\remote
NewGroup = ""

Backdoor Routine

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

  • Perform Remote Shell
  • Log Keystrokes
  • Manipulate Registry
  • File System Manipulation(Create, Change Attributes, Delete,Copy Files/Folders)
  • Update Itself
  • Download File
  • Remove Itself
  • Execute files
  • Search Files
  • Manipulate Mouse Movement
  • Get Camera information
  • List Running Processes
  • File Search
  • Connect to URL
  • Capture Audio
  • Capture Screenshot
  • Upload File
  • Capture Webcam

It connects to the following websites to send and receive information:

  • {BLOCKED}2.{BLOCKED}p.biz:9090

Information Theft

This backdoor steals the following information:

  • User Credentials
  • FTP Credential
  • Computer Name
  • Installed Antivirus software and Firewall Products
  • Locale Info
  • Operating System

Other Details

This backdoor deletes itself after execution.

NOTES:

It opens the following hidden process(es) and injects code to it:

  • Chrome

It has Anti-VM capabilities which made it not run in certain environments.

  SOLUTION

Minimum Scan Engine: 9.700
FIRST VSAPI PATTERN FILE: 10.662.04
FIRST VSAPI PATTERN DATE: 13 Mar 2014
VSAPI OPR PATTERN File: 10.663.00
VSAPI OPR PATTERN Date: 14 Mar 2014

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

Scan your computer with your Trend Micro product and note files detected as BKDR_REBHIP.YH

Step 3

Restart in Safe Mode

[ Learn More ]

Step 4

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.
  • %System Root%\directory

Step 5

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.
  • %Application Data%\{username}-wchelper.dll
  • %User Temp%\{username}{number}
  • %Application Data%\DC0C021C\{date}
  • %Application Data%\DC0C021C\ak.tmp

Step 6

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_LOCAL_MACHINE\SOFTWARE\Microsoft\Active Setup\Installed Components
    • {GUID}
  • In HKEY_CURRENT_USER\Software
    • remote

Step 7

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
    • HKLM = "%System Root%\directory\CyberGate\install\server.exe"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • HKCU = "%System Root%\directory\CyberGate\install\server.exe "
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\policies\Explorer\Run
    • Policies = "%System Root%\directory\CyberGate\install\server.exe"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer\Run
    • Policies = "%System Root%\directory\CyberGate\install\server.exe"

Step 8

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