Analysis by: Cris Nowell Pantanilla

 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: 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: 118,831 bytes
File Type: Other
Memory Resident: Yes
Initial Samples Received Date: 16 Dec 2016
Payload: 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 injects threads into the following normal process(es):

  • svchost.exe
  • msiexec.exe

Autostart Technique

This backdoor registers as a system service to ensure its automatic execution at every system startup by adding the following registry keys:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\TOSRSPRO
ImagePath = %Malware Path%\VMwareCplLauncher.exe

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\TOSRSPRO
DisplayName = "TrendMicro Officescan Security Reporting Service."

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\TOSRSPRO
Description = "TrendMicro Officescan Security Reporting Service."

Backdoor Routine

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

  • Manage files, registries, services and directories
  • Log keystrokes and active window
  • Restart/Reboot/Shutdown system
  • Enumerate processes
  • Terminate processes
  • Get drive information
  • Enumerate network resources
  • Set TCP connection state
  • Perfrom port mapping
  • Capture screen
  • Perform remote shell
  • Connect to SQL Database

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

  • film.{BLOCKED}ydayfilmlink.com:80

Other Details

This backdoor requires the following additional components to properly run:

  • %Malware Path%\VMwareCplLauncher.exe ← loads vmtools.dll
  • %Malware Path%\vmtools.dll ← plugx loader (TROJ_PLUGX.DUKPR)

  SOLUTION

Minimum Scan Engine: 9.800
FIRST VSAPI PATTERN FILE: 12.936.04
FIRST VSAPI PATTERN DATE: 03 Dec 2016
VSAPI OPR PATTERN File: 12.937.00
VSAPI OPR PATTERN Date: 04 Dec 2016

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. Before you could do this, you must restart in Safe Mode. For instructions on how to do this, you may refer to this page If the preceding step requires you to restart in safe mode, you may proceed to edit the system registry.

 
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services
    • TOSRSPRO

Step 4

Search and delete these files

[ 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.
%Malware Path%\VMwareCplLauncher.exe
%Malware Path%\vmtools.dll

Step 5

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