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BKDR_POISON.TUHC

January 30, 2017
 PLATFORM:

Windows

 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:

Dropped by other malware, Downloaded from the Internet

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. However, as of this writing, the said sites are inaccessible.

  TECHNICAL DETAILS

File Size:

53,248 bytes

File Type:

DLL

Memory Resident:

Yes

Initial Samples Received Date:

20 Jan 2017

Payload:

Connects to URLs/IPs, Steals information, Deletes files, Logs keystrokes

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 adds the following mutexes to ensure that only one of its copies runs at any one time:

  • hfdkoream

Autostart Technique

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Active Setup\Installed Components\{random GUID}
StubPath = "{malware path and file name}"

It is a .DLL file that adds the following services:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SymantecAuthdService
ImagePath = "{Malware Path}\mcods.exe"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SymantecAuthdService
Display Name = Symantec Authorization Service

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SymantecAuthdService
Description = Symantec Authorization and authentication service for starting and accessing secure machines

Backdoor Routine

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

  • Capture screen shots, webcam, audio
  • Delete, search, and upload files
  • Download and inject remote codes to legitimate processes
  • Log keystrokes and active window
  • Manage processes and services
  • Modify and search the registry entries
  • Perform a shell command
  • Send system information (IP address, computer name, user name, operating system)
  • Update/Uninstall the malware
  • View and terminate active windows and ports

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

  • musiconline.{BLOCKED}e.com:443
  • {BLOCKED}.{BLOCKED}.160.216:443

However, as of this writing, the said sites are inaccessible.

Other Details

This backdoor requires the existence of the following files to properly run:

  • {Malware Path}\mcods.exe <- non-malicious, used by the malware to load the malicious dll

It does the following:

  • It queries the default web browser by accessing the following registry entry:
    • HKEY_CLASSES_ROOT\http\shell\open\command
  • It then launches a hidden Web browser process (e.g. iexplore.exe) and then injects its code to the said process.

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

13.168.04

FIRST VSAPI PATTERN DATE:

20 Jan 2017

VSAPI OPR PATTERN File:

13.169.00

VSAPI OPR PATTERN Date:

21 Jan 2017

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

Note that not all files, folders, and registry keys and entries are installed on your computer during this malware's/spyware's/grayware's execution. This may be due to incomplete installation or other operating system conditions. If you do not find the same files/folders/registry information, please proceed to the next step.

Step 3

Restart in Safe Mode

[ Learn More ]

Step 4

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\SYSTEM\CurrentControlSet\Services
    • SymantecAuthdService

Step 5

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\Active Setup\Installed Components\{random GUID}
    • StubPath = {malware path and file name}

Step 6

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