BKDR_COBEACON.ZLFL-A

 Analysis by: Arvin Roi Macaraeg

 ALIASES:

VirTool:Win32/Atosev.A(MICROSOFT),

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

  TECHNICAL DETAILS

File Size:

210,944 bytes

File Type:

DLL

Memory Resident:

No

Initial Samples Received Date:

06 Dec 2018

Payload:

Connects to URLs/IPs, 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.

Backdoor Routine

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

  • Add or modify an environment variable
  • Alternate Parent Process
  • Change file time
  • Escalate privilege
  • File System Commands
  • Get Drives
  • Inject Code into a process
  • List Processes
  • Manage Service
  • Open a process
  • Sleep
  • Steal or Make token
  • Terminate process
  • Use and Purge Kerberos Tickets
  • Create, Connect and Disconnect to named pipe
  • Modify file
  • Set Current Directory
  • Write a binary file
  • Search for string in a file
  • Create Process
  • Check Loopback address
  • Find File
  • Create a directory
  • Delete a directory

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

  • https://{BLOCKED}.{BLOCKED}.225.68/z/msnbc2_live01@3121/manifest.f4m?hdcore=3.1&g={Encrypted Environment Information}

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

Information Theft

This Backdoor gathers the following data:

  • Malware Process ID
  • Operating System Version
  • IP address
  • Computer name
  • User name

Other Details

This Backdoor does the following:

  • This backdoor creates the following header to cover for the connection with the malicious URL:
    • https://{BLOCKED}prod-lh.akamaihd.net/z/msnbc2_live01@3121/manifest.f4m?hdcore=3.1&g={Encrypted Environment Information}

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

14.670.04

FIRST VSAPI PATTERN DATE:

06 Dec 2018

VSAPI OPR PATTERN File:

14.671.00

VSAPI OPR PATTERN Date:

07 Dec 2018

Step 1

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 2

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

Step 3

Identify and terminate files detected as BKDR_COBEACON.ZLFL-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

Scan your computer with your Trend Micro product to delete files detected as BKDR_COBEACON.ZLFL-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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