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Backdoor.Win32.SHADOWPAD.RJM

June 05, 2023
 ALIASES:

Win32:Evo-gen [Trj] (AVAST)

 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.

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

  TECHNICAL DETAILS

File Size:

6,541,312 bytes

File Type:

DLL

Memory Resident:

No

Initial Samples Received Date:

25 May 2023

Payload:

Connects to URLs/IPs, Modifies system registry

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%\MicroSoft.NET\AppLaunch.exe - If it isn't run on MicroSoft.NET Folder
  • %All Users Profile%\MicroSoft.NET\mscoree.dll - If it isn't run on MicroSoft.NET Folder

(Note: %All Users Profile% is the common user's profile folder, which is usually C:\Documents and Settings\All Users on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\ProgramData on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit). )

It adds the following processes:

  • %System%\svchost.exe

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

It creates the following folders:

  • %All Users Profile%\MicroSoft.NET\

(Note: %All Users Profile% is the common user's profile folder, which is usually C:\Documents and Settings\All Users on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\ProgramData on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit). )

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

  • Global\VDJPXBLDHTBZBXLVP

It injects codes into the following process(es):

  • %System%\svchost.exe

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

Other System Modifications

This Backdoor adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\KZF
KZF = {Hex values}

Backdoor Routine

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

  • TCP://{BLOCKED}c.{BLOCKED}1.info:{80, 443, 8080}

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

Other Details

This Backdoor adds the following registry keys:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
DDJJPBXTNXNR

It requires the existence of the following files to properly run:

  • AppLaunch.exe

It does the following:

  • It requires to be loaded by %All Users Profile%\MicroSoft.NET\AppLaunch.exe to perform its malicious routine

(Note: %All Users Profile% is the common user's profile folder, which is usually C:\Documents and Settings\All Users on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\ProgramData on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit). )

  SOLUTION

Minimum Scan Engine:

9.800

FIRST VSAPI PATTERN FILE:

18.490.04

FIRST VSAPI PATTERN DATE:

05 Jun 2023

VSAPI OPR PATTERN File:

18.491.00

VSAPI OPR PATTERN Date:

06 Jun 2023

Step 1

Trend Micro Predictive Machine Learning detects and blocks malware at the first sign of its existence, before it executes on your system. When enabled, your Trend Micro product detects this malware under the following machine learning name:

    • Troj.Win32.TRX.XXPE50FFF068

Step 2

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.
  • %All Users Profile%\MicroSoft.NET\

Step 3

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.
  • %All Users Profile%\MicroSoft.NET\AppLaunch.exe
  • %All Users Profile%\MicroSoft.NET\mscoree.dll

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_LOCAL_MACHINE\SOFTWARE\KZF
    • KZF = {Hex values}

Step 5

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\KZF
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\DDJJPBXTNXNR

Step 6

Scan your computer with your Trend Micro product to delete files detected as Backdoor.Win32.SHADOWPAD.RJM. 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 the following Trend Micro Support pages for more information:


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