Author: Jemimah Mae Molina   

 PLATFORM:

Windows, Unix, Linux

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

  • Threat Type:
    Backdoor

  • Destructiveness:
    No

  • Encrypted:
    Yes

  • In the wild:
    Yes

  OVERVIEW

INFECTION CHANNEL: Downloaded from specific site, Dropped by other malware

This backdoor comes bundled with a Monero miner, both spread by a botnet. The techniques employed are reminiscent of the Outlaw hacking group that Trend Micro reported in November 2018.

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 connects to Internet Relay Chat (IRC) servers. It joins an Internet Relay Chat (IRC) channel.

  TECHNICAL DETAILS

File size: 47,407 bytes
File type: Other
Memory resident: Yes
INITIAL SAMPLES RECEIVED DATE: 19 December 2019
PAYLOAD: Connects to URLs/IPs, Receive commands

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.

Installation

This Backdoor drops the following files:

  • {home directory}/.ssh/authorized_keys → saves the attacker's SSH public-key

Backdoor Routine

This Backdoor connects to any of the following Internet Relay Chat (IRC) servers:

  • {BLOCKED}.{BLOCKED}.148.125:443

It joins any of the following Internet Relay Chat (IRC) channels:

  • #007

It accesses a remote Internet Relay Chat (IRC) server where it receives the following commands from a remote malicious user:

  • Scan ports 21, 22, 23, 25, 53, 80, 110, 143, 6665 of a specific IP
  • Download a file
  • Scan open ports of a specific hostname
  • UDP Flooding
  • Connect to an arbitrary socket
  • Simultaneous IGMP, ICMP, UDP and TCP flooding on open ports with statistic report
  • IRC Control:
    • join → join a specified channel
    • part → leave a specified channel
    • rejoin → leave then rejoin a specified channel
    • op → grant a user an operator status
    • deop → revoke a user's operator status
    • voice → grant a user a voice status
    • devoice → revoke a user's voice status
    • msg → send a private message
    • flood → send a private message for a specified number of times
    • ctcpflood → send a client-to-client protocol request to a specified user or channel for a specified number of times
    • ctcp → send a client-to-client protocol request to a specified user or channel
    • invite → invite a user to join a specified channel
    • nick → change nickname
    • conecta → connect to a specified server
    • send → establish a direct connection with another user
    • raw → toggles raw events processing
    • eval → execute specified command
    • entra → join a channel after random seconds
    • sai → leave a channel after random seconds
    • sair → disconnect from the server
    • novonick → change nickname to x{random number}
    • estatisticas → toggles statistics flag
    • pacotes → toggles packets flag

  SOLUTION

Minimum scan engine: 9.850
First VSAPI Pattern File: 15.568.03
First VSAPI Pattern Release Date: 19 December 2019
VSAPI OPR PATTERN-VERSION: 15.569.00
VSAPI OPR PATTERN DATE: 20 December 2019

Step 1

Before doing any scans, Windows 7, Windows 8, Windows 8.1, and Windows 10 users must disable System Restore to allow full scanning of their computers.

Step 2

Scan your computer with your Trend Micro product to delete files detected as Backdoor.SH.SHELLBOT.AA. 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:


Did this description help? Tell us how we did.