ELF_VPNFILT.C

June 07, 2018
 Analysis by: Noel Anthony Llimos
 ALIASES:

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

 PLATFORM:

Linux

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

  • 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 Jun 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 DATE:

07 Jun 2018

VSAPI OPR PATTERN File:

14.303.00

VSAPI OPR PATTERN Date:

08 Jun 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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