Analysis by: Noel Anthony Llimos

ALIASES:

HEUR:Backdoor.Linux.Vpnfilter.a (Kaspersky), ELF.Linux.VPNFilter.GC (Quickheal)

 PLATFORM:

Linux

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

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 may be downloaded by other malware/grayware from remote 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: 296,600 bytes
File Type: ELF
Memory Resident: Yes
Initial Samples Received Date: 25 May 2018

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.

It may be downloaded by the following malware/grayware from remote sites:

Installation

This Backdoor adds the following folders:

Backdoor Routine

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

  • Terminate its current process
  • Reboot the infected device
  • Delays the reboot of the device
  • Read local file contents
  • Execute commands or another plugin with the following Linux Shell Commands:
    • /bin/sh
    • /bin/ash
    • /bin/bash
    • /bin/shell
  • Delete system files, and directories
  • Set its C&C proxy
  • Set its C&C proxy port
  • Set its other configuration parameters

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

  • {BLOCKED}skd4gipkm.onion/bin32/update.php
  • {BLOCKED}.{BLOCKED}.180.60
  • {BLOCKED}.{BLOCKED}.202.40
  • {BLOCKED}.{BLOCKED}.179.14
  • {BLOCKED}.{BLOCKED}.209.33
  • {BLOCKED}.{BLOCKED}.250.54
  • {BLOCKED}.{BLOCKED}.180.229
  • {BLOCKED}.{BLOCKED}.242.124
  • {BLOCKED}.{BLOCKED}.109.209
  • {BLOCKED}.{BLOCKED}.13.76
  • {BLOCKED}.{BLOCKED}.203.144
  • {BLOCKED}.{BLOCKED}.80.82
  • {BLOCKED}.{BLOCKED}.222.68
  • {BLOCKED}.{BLOCKED}.198.231

Information Theft

This Backdoor gathers the following data:

  • Mac Address
  • Platform Version
  • IP Address
  • Bootloader

  SOLUTION

Minimum Scan Engine: 9.850
FIRST VSAPI PATTERN FILE: 14.282.07
FIRST VSAPI PATTERN DATE: 24 May 2018
VSAPI OPR PATTERN File: 14.283.00
VSAPI OPR PATTERN Date: 25 May 2018

Step 1

Scan your computer with your Trend Micro product to delete files detected as ELF_VPNFILT.B. 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:

Step 2

Search and delete this folder

[ 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. DATA_GENERIC
  • In the Look In drop-down list, select My Computer, then press Enter.
  • Once located, select the folder then press SHIFT+DELETE to permanently delete the folder.

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