Analysis by: Homer Pacag
ALIASES:

TrojanDropper:Win32/GlassRat.A!RAT (Microsoft); Win32/GlassRAT.A (ESET-NOD32)

 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

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 retrieves specific information from the affected system.

It deletes itself after execution.

  TECHNICAL DETAILS

File Size: 36,864 bytes
Memory Resident: Yes
Initial Samples Received Date: 04 Dec 2015

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 and executes the following files:

  • %All Users Profile%\Application Data\{random}.dll - will be executed using %System%\rundll32.exe with parameters AddNum

(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)

Autostart Technique

This backdoor modifies the following registry entries to ensure it automatic execution at every system startup:

HKLM\SYSTEM\ControlSet002\
Services\RasAuto\Parameters
ServiceDll = %All Users Profile%\Application Data\{random}.dll

Backdoor Routine

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

  • Run cmd commands and Get responses from executed cmd commands
  • Initiate and terminate pipe/thread
  • Read file from directories
  • Execute/Create new processs
  • Upload/Dowload file

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

  • qx.{BLOCKED}s.com
  • mx.{BLOCKED}s.com
  • xx.{BLOCKED}s.com

Information Theft

This backdoor retrieves the following information from the affected system:

  • Computer Name
  • OS Version
  • IP Address

Other Details

This backdoor deletes itself after execution.

  SOLUTION

Minimum Scan Engine: 9.800
FIRST VSAPI PATTERN FILE: 12.190.04
FIRST VSAPI PATTERN DATE: 04 Dec 2015
VSAPI OPR PATTERN File: 12.191.00
VSAPI OPR PATTERN Date: 04 Dec 2015

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

Restore this modified 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\SYSTEM\ControlSet002\Services\RasAuto\Parameters
    • ServiceDll = %System%\rasauto.dll

Step 4

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. DATA_GENERIC
  • In the Look In drop-down list, select My Computer then press Enter.
  • Once located, select the file then press SHIFT+DELETE to delete it.
    *Note: The file name input box title varies depending on the Windows version (e.g. Search for files or folders named or All or part of the file name.).

    • • For Windows Vista, Windows 7, Windows Server 2008, Windows 8, Windows 8.1, and Windows Server 2012:

    1. Open a Windows Explorer window.
      • For Windows Vista, 7, and Server 2008 users, click Start>Computer.
      • For Windows 8, 8.1, and Server 2012 users, right-click on the lower left corner of the screen, then click File Explorer.
    2. In the Search Computer/This PC input box, type:
      DATA_GENERIC
    3. Once located, select the file then press SHIFT+DELETE to delete it.
      *Note: Read the following Microsoft page if these steps do not work on Windows 7.

    Step 5

    Restart in Safe Mode

    [ Learn More ]

    Step 6

    Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_GLASSRAT.B. 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 7

    Scan your computer with your Trend Micro product to delete files detected as BKDR_GLASSRAT.B. 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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