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Backdoor.Win32.COBEACON.A

April 12, 2019
 Analysis by: John Anthony Banes
 ALIASES:

Trojan.CobaltStrike.G (BitDefender)

 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 certain websites to send and receive information.

  TECHNICAL DETAILS

File Size:

14,848 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

11 Apr 2019

Payload:

Connects to URLs/IPs, Downloads files

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 adds the following processes:

  • rundll32.exe

It injects codes into the following process(es):

  • added rundll32.exe process

Backdoor Routine

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

  • Execute PowerShell commands
  • Upload/Download files
  • Manage files
  • Manage services
  • Read/Modify file time
  • Obtain/Create access tokens
  • Impersonate tokens
  • Open processes
  • Inject codes to processes
  • Adjust permissions in process
  • Connect to a named pipe
  • Use/Purge Kerberos tickets
  • Escalate privileges

Other Details

This Backdoor connects to the following website to send and receive information:

  • http://{BLOCKED}.{BLOCKED}.25.171:887/g.pixel
  • http://{BLOCKED}.{BLOCKED}.25.171:887/submit.php?id={numbers}

It does the following:

  • This malware starts the following service:
    • DceRpcSs
  • It requires connecting to the following site to download and execute additional code in memory:
    • http://{BLOCKED}.{BLOCKED}.25.171:887/xMc4

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

14.934.04

FIRST VSAPI PATTERN DATE:

12 Apr 2019

VSAPI OPR PATTERN File:

14.935.00

VSAPI OPR PATTERN Date:

13 Apr 2019

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

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

Identify and terminate files detected as Backdoor.Win32.COBEACON.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 4

Disable this malware service

[ Learn More ]
  •  
    • DceRpcSs

Step 5

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


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