Analysis by: Jeanne Jocson
ALIASES:

Linux/Luabot.A (NOD32), Backdoor:Linux/Luabot.A (Microsoft)

 PLATFORM:

Linux

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted: Yes

  • 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 listens on ports.

It performs denial of service (DoS) attacks on affected systems using specific flooding method(s).

It connects to certain websites to send and receive information.

  TECHNICAL DETAILS

File Size: 996,512 bytes
File Type: ELF
Memory Resident: Yes
Initial Samples Received Date: 26 Sep 2016
Payload: Launches DoS/DDoS attacks

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 listens on the following ports:

  • 11833

Denial of Service (DoS) Attack

This Backdoor performs denial of service (DoS) attacks on affected systems using the following flooding method(s):

  • HTTP GET request to the local host

Other Details

This Backdoor connects to the following URL(s) to check for an Internet connection:

  • google.com
  • facebook.com
  • baidu.com
  • amazon.com
  • wikipedia.org

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

  • {BLOCKED}.{BLOCKED}.3.47:1085
  • {BLOCKED}.{BLOCKED}.249.9

It does the following:

  • Opens file socket: bbot_mutex_203508
  • Checks active sockets
  • Gets active process names and PID
  • Checks the current user's privilege
  • Checks the network interface name and its IP
  • Changes the setting of iptables(Linux firewall)

NOTES:

  • Assembles BotID:

    "Bot id is \t{IFACE-NAME}-{IPADDR}-{6 random numbers}:{Version}"

    Where:

    IFACE-NAME = network interface name

    IP-ADDR = host's IP

    Version = bot's version

  • HTTP GET request to 217.23.3.47:

    GET "/bot?bid={IFACE}-{IPaddr}-{6 random numbers}:{mutex} HTTP/1.1\r\n"

    where:

    IFACE = network interface

    IPaddr = host's IP

    mutex = "203508"

  SOLUTION

Minimum Scan Engine: 9.800
FIRST VSAPI PATTERN FILE: 12.800.05
FIRST VSAPI PATTERN DATE: 26 Sep 2016
VSAPI OPR PATTERN File: 12.801.00
VSAPI OPR PATTERN Date: 27 Sep 2016

Restart in normal mode and scan your computer with your Trend Micro product for files detected as ELF_LUABOT.A. 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 this Knowledge Base page for more information.


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