Analysis by: Bren Matthew Ebriega
ALIASES:

Trojan:Win32/Glupteba.MD!MTB (MICROSOFT); Malicious_Behavior.SB (FORTINET)

 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

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.

  TECHNICAL DETAILS

File Size: 89,088 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 09 Dec 2020
Payload: Connects to URLs/IPs, Collects system 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\{Random characters}.job → same as the filename of created copy

(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:

  • %All Users Profile%\{Random characters}\{Random characters}.exe

(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:

  • %All Users Profile%\{Random characters}\{Random characters}.exe start

(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 creates the following folders:

  • %All Users Profile%\{Random characters}

(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 terminates itself if it finds the following processes in the affected system's memory:

  • a2guard.exe

Backdoor Routine

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

  • Execute Arbitrary Commands via VBS, BAT,CMD and PS1 Files
  • Execute EXE and DLL files

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

  • {BLOCKED}08.com:4039
  • {BLOCKED}08.xyz:4039
  • {BLOCKED}.{BLOCKED}.244.244
  • {BLOCKED}.{BLOCKED}.21.38
  • {BLOCKED}.{BLOCKED}.81.140
  • {BLOCKED}.{BLOCKED}.164.118
  • {BLOCEKD}.{BLOCKED}.206.212
  • {BLOCKED}.{BLOCEKD}.40.189
  • {BLCOEKD}.{BLOCKED}.175.225
  • {BLOCKED}.{BLOCKED}.193.9
  • {BLOCKED}.{BLOCKED}.0.34
  • {BLOCKED}.{BLOCKED}.0.39

Information Theft

This Backdoor gathers the following data:

  • Username
  • System Architecture
  • Volume Serial Number
  • Windows Build Number

Other Details

This Backdoor does the following:

  • If it is started with no parameters, it does the following:
    • Create the folder that would contain its copy.
    • Drop its copy in the created folder.
    • Create the scheduled task and run the said scheduled task.

It accepts the following parameters:

  • start → Start main routine.

It adds the following scheduled tasks:

  • Task Name: \{Random characters} → same as the filename of created copy
    Trigger: Every 2 mins for the duration of 1 day
    Action: %All Users Profile%\{Random characters}\{Random characters}.exe start

(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: 16.630.04
FIRST VSAPI PATTERN DATE: 01 Apr 2021
VSAPI OPR PATTERN File: 16.631.00
VSAPI OPR PATTERN Date: 02 Apr 2021

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.XXPE50FFF042

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

Restart in Safe Mode

[ Learn More ]

Step 5

Identify and terminate files detected as Backdoor.Win32.SYSTEMBC.A

[ Learn More ]
  1. Windows Task Manager may not display all running processes. In this case, please use a third-party process viewer, preferably Process Explorer, to terminate the malware/grayware/spyware file. You may download the said tool here.
  2. If the detected file is displayed in either Windows Task Manager or Process Explorer but you cannot delete it, restart your computer in safe mode. To do this, refer to this link for the complete steps.
  3. If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.

Step 6

Deleting Scheduled Tasks

The following {Task Name} - {Task to be run} listed should be used in the steps identified below:

  • Task name: {Random characters}
    Task to be run: %All Users Profile%\{Random characters}\{Random characters}.exe start

For Windows 2000, Windows XP, and Windows Server 2003:

  1. Open the Windows Scheduled Tasks. Click Start>Programs>Accessories>
    System Tools>Scheduled Tasks.
  2. Locate each {Task Name} values listed above in the Name column.
  3. Right-click on the said file(s) with the aforementioned value.
  4. Click on Properties. In the Run field, check for the listed {Task to be run}.
  5. If the strings match the list above, delete the task.

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

  1. Open the Windows Task Scheduler. To do this:
    • On Windows Vista, Windows 7, and Windows Server 2008, click Start, type taskschd.msc in the Search input field, then press Enter.
    • On Windows 8, Windows 8.1, and Windows Server 2012, right-click on the lower left corner of the screen, click Run, type taskschd.msc, then press Enter.
  2. In the left panel, click Task Scheduler Library.
  3. In the upper-middle panel, locate each {Task Name} values listed above in the Name column.
  4. In the lower-middle panel, click the Actions tab. In the Details column, check for the {Task to be run} string.
  5. If the said string is found, delete the task.

Step 7

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%\{Random characters}

Step 8

Restart in normal mode and scan your computer with your Trend Micro product for files detected as Backdoor.Win32.SYSTEMBC.A. 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.


Did this description help? Tell us how we did.