Backdoor.Win32.SYSTEMBC.G

September 29, 2023
 Analysis by: Raighen Sanchez
 ALIASES:

Trojan:Win32/Cobaltstrike.AR!Cert (MICROSOFT)

 PLATFORM:

Windows

 OVERALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:
 INFORMATION EXPOSURE:

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted:

  • 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.

  TECHNICAL DETAILS

File Size:

644,672 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

26 Sep 2023

Payload:

Collects system information, Connects to URLs/IPs, Drops files, Steals information

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 files:

  • %Windows%\Tasks\{malware filename}.job

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

It drops the following copies of itself into the affected system:

  • %ProgramData%\{random alphabet characters}\{6 random alphabet characters}.exe

(Note: %ProgramData% is a version of the Program Files folder where any user on a multi-user computer can make changes to programs. This contains application data for all users. This is usually C:\ProgramData on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit), or C:\Documents and Settings\All Users on Windows Server 2003(32-bit), 2000(32-bit) and XP.)

It creates the following folders:

  • %ProgramData%\{random alphabet characters}

(Note: %ProgramData% is a version of the Program Files folder where any user on a multi-user computer can make changes to programs. This contains application data for all users. This is usually C:\ProgramData on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit), or C:\Documents and Settings\All Users on Windows Server 2003(32-bit), 2000(32-bit) and XP.)

Information Theft

This Backdoor gathers the following data:

  • Hostname
  • Number of Processors
  • OS Version
  • Processor Architecture
  • Username
  • Local IP Address

Other Details

This Backdoor connects to the following URL(s) to get the affected system's IP address:

  • https://{BLOCKED}fy.org/
  • https://{BLOCKED}ip.org/

It connects to the following possibly malicious URL:

  • http://{BLOCKED}.{BLOCKED}.{BLOCKED}.244
  • http://{BLOCKED}.{BLOCKED}.{BLOCKED}.38
  • http://{BLOCKED}.{BLOCKED}.{BLOCKED}.40
  • http://{BLOCKED}.{BLOCKED}.{BLOCKED}.118
  • http://{BLOCKED}.{BLOCKED}.{BLOCKED}.212
  • http://{BLOCKED}.{BLOCKED}.{BLOCKED}.189
  • http://{BLOCKED}.{BLOCKED}.{BLOCKED}.225
  • http://{BLOCKED}.{BLOCKED}.{BLOCKED}.9
  • http://{BLOCKED}.{BLOCKED}.{BLOCKED}.34
  • http://{BLOCKED}.{BLOCKED}.{BLOCKED}.39

It adds the following scheduled tasks:

  • Task Name: {malware filename}
    Trigger: %ProgramData%\{random alphabet characters}\{6 random alphabet characters}.exe
    Duration:Repeats every 02:00:00 AM

(Note: %ProgramData% is a version of the Program Files folder where any user on a multi-user computer can make changes to programs. This contains application data for all users. This is usually C:\ProgramData on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit), or C:\Documents and Settings\All Users on Windows Server 2003(32-bit), 2000(32-bit) and XP.)

  SOLUTION

Minimum Scan Engine:

9.800

FIRST VSAPI PATTERN FILE:

18.723.00

FIRST VSAPI PATTERN DATE:

27 Sep 2023

VSAPI OPR PATTERN File:

18.723.00

VSAPI OPR PATTERN Date:

27 Sep 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.XXPE50FFF073

Step 2

Before doing any scans, Windows 7, Windows 8, Windows 8.1, and Windows 10 users must disable System Restore to allow full scanning of their computers.

Step 3

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 4

Deleting Scheduled Tasks while in Safe Mode

  1. Still in safe mode, the following {Task Name}-{Task to be run} listed should be used in the steps identified below:
    • Task name: {malware filename}
      Task to be run: %ProgramData%\{random}\{malware filename}.exe
  2. For Windows 7 and Server 2008 (R2) users, click Start>Computer.
    • For Windows 8, 8.1, 10, and Server 2012 users, right-click on the lower left corner of the screen, then click File Explorer.
  3. In the Search Computer/This PC input box, type:
    • %System%\Tasks\{Task Name}
  4. Once located, select the file then press SHIFT+DELETE to delete it.
  5. Open Registry Editor. To do this:
    • For Windows 7 and Server 2008 (R2) users, click the Start button, type regedit in the Search input field, and press Enter.
    • For Windows 8, 8.1, 10, and Server 2012 (R2) users, right-click on the lower left corner of the screen, click Run, type regedit in the text box
  6. In the left panel of the Registry Editor window, double-click the following:
    • HKEY_LOCAL_MACHINE>SOFTWARE>Microsoft>Windows NT>CurrentVersion>Schedule>TaskCache>Tree>{Task Name}
  7. Locate the created entry and take note of the registry value's data:
    • ID={Task Data}
  8. After taking note of the data, delete the registry key:
    • HKEY_LOCAL_MACHINE>SOFTWARE>Microsoft>Windows NT>CurrentVersion>Schedule>TaskCache>Tree>{Task Name}
  9. In the left panel of the Registry Editor window, double-click the following:
    • HKEY_LOCAL_MACHINE>SOFTWARE>Microsoft>Windows NT>CurrentVersion>Schedule>TaskCache>Tasks
  10. Still in the left panel, locate and delete the registry key with the same name as the located Task Data in step #6:
    • ={Task Data}
  11. Close Registry Editor.

Step 5

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.
  • %ProgramData%\{random alphabet characters}

Step 6

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.
  • %ProgramData%\{random alphabet characters}\{6 random alphabet characters}.exe
  • %Windows%\Tasks\{malware filename}.job

Step 7

Scan your computer with your Trend Micro product to delete files detected as Backdoor.Win32.SYSTEMBC.G. 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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