Backdoor.Linux.BASHLITE.WWLP

June 18, 2020
 Analysis by: Patrick Noel Collado
 ALIASES:

DDoS:Linux/Mirai.PA!MTB (Microsoft), HEUR:Backdoor.Linux.Gafgyt.a (Kaspersky)

 PLATFORM:

Linux

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted:

  • 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 accesses websites to download files. This action allows this malware to possibly add other malware on the affected computer.

  TECHNICAL DETAILS

File Size:

130,121 bytes

File Type:

ELF

Memory Resident:

Yes

Initial Samples Received Date:

12 Jun 2020

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.

Backdoor Routine

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

  • HTTP - HTTP Flood
  • UDP - UDP Flood
  • CUDP - UDP Flood but with prerequisite conditional checking
  • STD - STD Flood
  • TCP - TCP Flood
  • CTCP - TCP Flood but with prerequisite conditional checking
  • XMAS - TCP (flags are set to high)
  • CXMAS - TCP (flags are set to high) but with prerequisite conditional checking
  • VSE - VSE flood or VSE flood with random strings
  • CVSE - VSE Flood or VSE Flood with random strings but with prerequisite conditional checking
  • CNC - set CNC
  • SYN - TCP Flood
  • ACK - TCP Flood
  • NIGGA - Terminate Process

It connects to the following URL(s) to send and receive commands from a remote malicious user:

  • {BLOCKED}.{BLOCKED}.197.105
  • {BLOCKED}.{BLOCKED}.181.37

Download Routine

This Backdoor accesses websites to download the following files:

  • scripts detected as Trojan.SH.MIRAI.BOH

Other Details

This Backdoor does the following:

  • It accesses /proc/net/route to obtain the gateway.
  • It connects to the Google's DNS server to obtain the IP address.

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

15.936.04

FIRST VSAPI PATTERN DATE:

17 Jun 2020

VSAPI OPR PATTERN File:

15.937.00

VSAPI OPR PATTERN Date:

18 Jun 2020

Scan your computer with your Trend Micro product to delete files detected as Backdoor.Linux.BASHLITE.WWLP. 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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