Backdoor.Win64.COBEACON.ZCLG.enc

 Analysis by: Leidryn Saludez

 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. It connects to a website to send and receive information.

  TECHNICAL DETAILS

File Size:

287,352 bytes

File Type:

Other

Initial Samples Received Date:

03 Jul 2024

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.

Backdoor Routine

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

  • Connect and disconnect to a named pipe
  • Escalate privileges
  • Execute arbitrary commands
  • Impersonate tokens
  • Inject code into processes
  • Manage directories (Create, Remove, Set Directory)
  • Manage files (List, Create, Delete, Modify, Rename, Copy)
  • Manage processes (List, Create, Terminate)
  • List Drive Information
  • Use/purge Kerberos tickets

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

  • http://{BLOCKED}g-f12b.azuer.workers.dev/feedback/js/help/prod/service/lazy.min.js
  • http://{BLOCKED}g-f12b.azuer.workers.dev/we/s/h36B915845CCD42D1_App_Scripts/jquery.signalR2.1.1.min.js

Information Theft

This Backdoor gathers the following data:

  • Username
  • Computer name
  • Operating System Version
  • Executable used to load the sample

Other Details

This Backdoor does the following:

  • It requires being loaded by mscorsvc.dll located in %windows%\assembly directory to decrypt the content of this file → detected as Backdoor.Win64.COBEACON.ZCLG
  • This sample needs to be located in the %windows%\assembly directory and have a file name of 'msco.conf' to execute properly.

  SOLUTION

Minimum Scan Engine:

9.800

FIRST VSAPI PATTERN FILE:

19.446.08

FIRST VSAPI PATTERN DATE:

04 Jul 2024

VSAPI OPR PATTERN File:

19.447.00

VSAPI OPR PATTERN Date:

05 Jul 2024

Step 1

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 2

Scan your computer with your Trend Micro product to delete files detected as Backdoor.Win64.COBEACON.ZCLG.enc. 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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