arrow_back
search
close

Ransom.SH.ESXIARGS.THBOFBC

March 13, 2023
 ALIASES:

Ransom:SH/ESXiArgs.A!MTB (MICROSOFT)

 PLATFORM:

Linux

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

  • Threat Type: Ransomware

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Downloaded from the Internet, Dropped by other malware

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

It encrypts files with specific file extensions. It drops files as ransom note.

  TECHNICAL DETAILS

File Size:

3,757 bytes

File Type:

Script

Memory Resident:

Yes

Initial Samples Received Date:

09 Feb 2023

Payload:

Encrypts files, Terminates processes, Displays message/message boxes

Arrival Details

This Ransomware 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 Ransomware drops the following files:

  • /tmp/public.pem ← Public RSA key used to encrypt the key

Other System Modifications

This Ransomware deletes the following files:

  • /store/packages/vmtools.py
  • All .log files
  • Itself and its component files

Process Termination

This Ransomware terminates the following processes if found running in the affected system's memory:

  • VMX related processes

Other Details

This Ransomware does the following:

  • It requires the following components in order to execute:
    • /tmp/encrypt ← Encryptor ELF executable
    • /tmp/encrypt.sh ← shell script that as the logic for the attack
    • /tmp/motd ← Ransom note in text form
    • /tmp/index.html ← Ransom note in HTML form
  • It overwrites /sbin/hostd-probe with /sbin/hostd-probe.bak
  • It establishes persistence by adding the following:
    • /bin/auto-backup.sh ← ESXI configuration file
    • Starting an SSH server on host "/etc/init.d/SSH start"
  • It executes differently depending on the VMware build version:
    • If build version is 7.0:
      - It modifies and overwrites the contents of /bin/hostd-probe file
    • If build version is not 7.0:
      - It deletes cronjobs
      - It recreates /var/spool/cron/crontabs/root file then deletes the original file

Ransomware Routine

This Ransomware encrypts files with the following extensions:

  • .vmdk
  • .vmx
  • .vmxf
  • .vmsd
  • .vmsn
  • .vswp
  • .vmss
  • .nvram
  • .vmem

It appends the following extension to the file name of the encrypted files:

  • .args

It drops the following file(s) as ransom note:

  • /etc/motd ← Ransom note in text form
  • /usr/lib/vmware/index.html ← Ransom note in HTML form

  SOLUTION

Minimum Scan Engine:

9.800

FIRST VSAPI PATTERN FILE:

18.254.03

FIRST VSAPI PATTERN DATE:

13 Feb 2023

VSAPI OPR PATTERN File:

18.255.00

VSAPI OPR PATTERN Date:

14 Feb 2023

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

Note that not all files, folders, and registry keys and entries are installed on your computer during this malware's/spyware's/grayware's execution. This may be due to incomplete installation or other operating system conditions. If you do not find the same files/folders/registry information, please proceed to the next step.

Step 3

Identify and terminate files detected as Ransom.SH.ESXIARGS.THBOFBC

[ Learn More ]
  1. Windows Task Manager may not display all running processes. In this case, please use a third-party process viewer, preferably Process Explorer, to terminate the malware/grayware/spyware file. You may download the said tool here.
  2. If the detected file is displayed in either Windows Task Manager or Process Explorer but you cannot delete it, restart your computer in safe mode. To do this, refer to this link for the complete steps.
  3. If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.

Step 4

Search and delete this file

[ Learn More ]
There may be some files that are hidden. Please make sure you check the Search Hidden Files and Folders checkbox in the "More advanced options" option to include all hidden files and folders in the search result.
  • /tmp/public.pem
  • /tmp/encrypt
  • /tmp/encrypt.sh
  • /tmp/motd
  • /tmp/index.html
  • /bin/auto-backup.sh
  • /bin/hostd-probe
  • /sbin/hostd-probe.bak
  • /var/spool/cron/crontabs/root
  • /etc/motd
  • /usr/lib/vmware/index.html

Step 5

Scan your computer with your Trend Micro product to delete files detected as Ransom.SH.ESXIARGS.THBOFBC. 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:

Step 6

Restore encrypted files from backup.


Did this description help? Tell us how we did.