Trojan.Linux.ZYX.USELVF319

September 03, 2019
 Analysis by: Wilbert Luy
 ALIASES:

HEUR:Backdoor.Linux.Agent.ca (Kaspersky), Trojan:Win32/CoinMiner.C!cl (Microsoft)

 PLATFORM:

Linux

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Downloaded from the Internet, Dropped by other malware

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.

However, as of this writing, the said sites are inaccessible.

  TECHNICAL DETAILS

File Size:

97,641 bytes

File Type:

ELF

Memory Resident:

Yes

Initial Samples Received Date:

05 Jun 2019

Payload:

Connects to URLs/IPs

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.

Download Routine

This Trojan connects to the following website(s) to download and execute a malicious file:

  • http://w.{BLOCKED}n.com:43768/init.sh

Other Details

This Trojan does the following:

  • It replaces the original rm of the system to perform malicious routine when rm is called and will still execute the original rm in /usr/bin/rmm.
  • It removes the immutable and append only properties of the following files and reverts it back after execution:
    • /var/spool/cron
    • /var/spool/cron/root
  • It does the following commands to create a scheduled task or cron job:
    • cat \'/var/spool/cron/root\' |grep init.sh 318
    • echo >> /var/spool/cron/root
  • It does the following commands:
    • chmod 644 /var/spool/cron/root
    • chattr +ia /etc/cron.d

However, as of this writing, the said sites are inaccessible.

  SOLUTION

Minimum Scan Engine:

9.850

VSAPI OPR PATTERN File:

15.151.00

VSAPI OPR PATTERN Date:

03 Jun 2019

Scan your computer with your Trend Micro product to delete files detected as Trojan.Linux.ZYX.USELVF319. 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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