Author: Noel Anthony Llimos   

 

Linux/VPNFilt-C (Sophos_LITE), Trojan:Linux/VPNFilt (Microsoft)

 PLATFORM:

Linux

 OVER ALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:
 INFORMATION EXPOSURE
Low
Medium
High
Critical

  • Threat Type:
    Trojan

  • Destructiveness:
    No

  • Encrypted:
    No

  • In the wild:
    Yes

  OVERVIEW

INFECTION CHANNEL: Dropped by other malware, Downloaded from the Internet

This Trojan may be downloaded by other malware/grayware from remote sites. It arrives as a component bundled with malware/grayware packages.

  TECHNICAL DETAILS

File size: 37,932 bytes
File type: ELF
Memory resident: Yes
INITIAL SAMPLES RECEIVED DATE: 08 June 2018
PAYLOAD: Steals information, Compromises network security, Terminates processes

Arrival Details

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

It arrives as a component bundled with malware/grayware packages.

Other System Modifications

This Trojan deletes the following files:

  • /var/run/vpnfilterm/htpx
  • /var/run/vpnfilter
  • /var/run/vpnfilterm/
  • /var/run/vpnfilterw/

Process Termination

This Trojan terminates the following processes if found running in the affected system's memory:

  • vpnfilter
  • security
  • tor

Information Theft

This Trojan gathers the following data:

  • HTTP authentication packets, which contains the following:
    • Username
    • Password
    • Level of Authorization
  • Modbus SCADA Protocols
  • Website Credentials

Other Details

This Trojan does the following:

  • It is capable of having the infected device unusable by deleting the following system files:
    • /var/tmp/client_ca.crt
    • /var/tmp/client.key
    • /var/tmp/client.crt
    • /var/run/vpn.tmp
    • /var/run/vpn.
    • /var/run/torrc
    • /var/run/tord/hidden_ssh/private_key
    • /var/run/tord/hidden_ssh/hostname
    • /var/run/tor
    • /var/run/msvf.pid
    • /var/run/client_ca.crt
    • /var/run/client.key
    • /var/run/client.crt
    • /var/pckg/mikrotik.
    • /var/pckg/.mikrotik.
    • /var/msvf.pid
    • /var/client_ca.crt
    • /var/client.key
    • /var/client.crt
    • /tmp/client_ca.crt
    • /tmp/client.key
    • /tmp/client.crt
    • /flash/nova/etc/loader/init.x3
    • /flash/nova/etc/init/security
    • /flash/nova/etc/devel-login
    • /flash/mikrotik.o
    • /flash/.mikrotik.
    • /var/run/tord/hidden_ssh/
    • /var/run/tord/
    • /flash/nova/etc/loader/
  • It renders the system unusable on restart by modifying the bytes of (/dev/mtdX ← Linux Flash Memory) with a 0xFF byte.
  • It deletes the remainder of the system files by executing the following command:
    • rm -rf /*
  • It is capable of intercepting network traffic
  • The intercepted data is stored into the file:
    • %DIR%/rep_%NUMBER%.bin
  • It creates its own TOR communication that will be used by ELF_VPNFILT.B

  SOLUTION

Minimum scan engine: 9.850
First VSAPI Pattern File: 14.302.08
First VSAPI Pattern Release Date: 07 June 2018
VSAPI OPR PATTERN-VERSION: 14.303.00
VSAPI OPR PATTERN DATE: 08 June 2018

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