Backdoor.Linux.BASHLITE.AMH

July 24, 2019
 Analysis by: Henry Alarcon Jr.
 ALIASES:

Linux/Mirai.B!tr.bdr (Fortinet), HEUR:Backdoor.Linux.Mirai.b (Kaspersky), ELF:Mirai-AGB [Trj] (Avast)

 PLATFORM:

Linux

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Downloaded from the Internet, Dropped by other malware

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.

  TECHNICAL DETAILS

File Size:

79,964 bytes

File Type:

ELF

File Compression:

UPX

Memory Resident:

No

Initial Samples Received Date:

27 May 2019

Payload:

Connects to URLs/IPs, Exploits vulnerability

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:

  • Clean device by doing the following:
    • It terminates processes that contains the following strings:
      • busybox
      • python
      • telnetd
      • perl
      • java
    • Delete all files found in the following folders:
      • /var/tmp/
      • /tmp/
      • /var/
      • /var/run/
      • /var/log/wtmp/
      • /bin/netstat/
    • Kills processes that uses the following ports:
      • 60274
      • 55812
      • 57886
      • 48101
      • 45837
      • 9765
      • 9473
      • 1991
      • 1337
      • 701
    • Flush IPTables
    • Stop Firewall
    • Clear bash history
  • Executes shell commands
  • Performs various DDOS attacks
  • Stop currently active backdoor command
  • Sends traffic to a specified address over a specified duration
  • Checks connection with the C&C

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

  • {BLOCKED}.{BLOCKED}.25.84:8010

Other Details

This Backdoor does the following:

  • It is capable of terminating processes which satisfies any of the following conditions:
    • Uses any of the following ports:
      • 62751
      • 60274
      • 55812
      • 57886
      • 48101
      • 47873
      • 45837
      • 36895
      • 34254
      • 24465
      • 20992
      • 20736
      • 20480
      • 10275
      • 9765
      • 9473
      • 5888
      • 5632
      • 1991
      • 1337
      • 701
    • Processes contains strings related to botnets
  • If it cannot connects to its URL(s) to send and receive commands from a remote malicious user then it will retrieve new C&C to the following URL:
    • https://{BLOCKED}in.com/raw/ByvbTFGe
  • It may spread to other devices by taking advantage of the following vulnerabilities:
  • over TELNET/ SSH bruteforce

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

15.136.05

FIRST VSAPI PATTERN DATE:

27 May 2019

VSAPI OPR PATTERN File:

15.137.00

VSAPI OPR PATTERN Date:

27 May 2019

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