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Threat Actors esxiargs

Description

ESXiArgs is a ransomware campaign that emerged in February 2023, targeting VMware ESXi servers by exploiting the CVE-2021-21974 vulnerability. It encrypts virtual machine configuration files (.vmdk, .vmx, .vmxf, .vmsd, .vmsn, .vswp, .vmss, .nvram, .vmem) rendering VMs inaccessible. The campaign compromised thousands of unpatched servers globally, primarily affecting European organizations. A decryptor was later released by CISA and FBI. 1 ransom note(s) on file

Goals & Targeting

Objectives

Ransomware
Financial Gain

AI Analysis

· 1 week ago

Executive Summary

ESXiArgs is a ransomware campaign targeting VMware ESXi servers via CVE-2021-21974. It encrypts virtual machine files, rendering them inaccessible and demanding payment for decryption. Thousands of European organizations were affected, with CISA and FBI releasing a decryptor.

Goals & Targeting

ESXiArgs aims for financial gain through ransom payments, targeting critical infrastructure sectors with VMware ESXi servers. Its regional focus on Europe suggests easier access or higher success rates there.

Enhanced Description

ESXiArgs emerged in February 2023, exploiting the CVE-2021-21974 vulnerability in VMware ESXi servers. It targets unpatched systems globally but primarily affected European organizations. The ransomware encrypts multiple VM configuration files, disrupting operations. CISA and FBI collaboration resulted in a decryptor to mitigate the threat.

Key Capabilities

  • Encryption of VM configuration files
  • Exploiting known vulnerabilities

MITRE ATT&CK Tactics

Data Encryption
Credential Access

ATT&CK Techniques

T1537.001

Software / Tooling

ESXiArgs

Campaigns & Victims

Campaign targeted unpatched VMware servers globally, primarily in Europe. Notable operation in February 2023 with significant impact.

IOC Patterns

  • Exploitation of CVE-2021-21974
  • VMware configuration file encryption

Recommended Actions

  • Patch systems against CVE-2021-21974
  • Monitor for VM file encryption activities
  • Implement network segmentation
  • Use endpoint detection tools
  • Maintain offline backups

Suggested Tags

Ransomware
CyberCrime

Confidence Assessment

High confidence in vulnerability exploit and ransomware activity, but limited details on TTPs beyond described attack vector.

ATT&CK Techniques

No techniques linked yet.

Software / Tooling

No tools linked yet.

Campaigns / Victims

No campaigns linked yet.

Observed Data

No observed data linked yet.

Indicators of Compromise

No IOCs linked yet.

References

No references recorded yet.

Intel Summary

0

Techniques

0

Tools

0

Campaigns

0

IOCs

0

Observed Data

0

Tactics

Tags

Ransomware
CyberCrime

Details

Type
Criminal
Sophistication
Medium
Primary Motivation
Organizational gain
Confidence
80%
Added
May 4, 2026
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