Malicious ESXiArgs Ransomware Public Key Drop in Temp Directory (via file_event)

ATT&CK techniques

Impact

Recon
Resource Dev
Initial Access
Execution
Persistence
Priv Esc
Defense Evasion
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact
- T1486Data Encrypted for Impact

What it detects

This rule detects creation of the public.pem encryption key file in the temporary directory of a VMware ESXi host, the key the ESXiArgs ransomware drops before encrypting virtual machine files following OpenSLP CVE-2021-21974 exploitation. This file drop is an early sign of an in-progress ransomware encryption of ESXi datastores.

Reporting behind it

Related detections9 linkedT1486 — drag to rearrange

Malicious TellYouThePass Ransomware Note Creation

Malicious CrazyHunter Ransomware Toolkit Execution from Public Directory

Malicious Black Basta ESXi Ransomware Volume Enumeration and Encryption via Command Line (via process_creation)

Malicious DarkAngels Linux Ransomware Ransom Note Creation via File System (via file_event)

Malicious DarkAngels Linux Ransomware Encrypted Extension and Log Artifacts via File System (via file_event)

Malicious Cyclops Ransomware File Artifacts (via file_event)

Malicious Mallox Ransomware Encryption Artifacts via Ransom Note and Extension (via file_event)

Malicious Backup and Recovery Destruction Chain via Dire Wolf Ransomware (via process_creation)

Malicious Dire Wolf Ransomware Encrypted File Extension on Disk (via file_event)

Malicious ESXiArgs Ransomware Public Key Drop in Temp Directory (via file_event)

Pivot detection · T1486 · 9 related

Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.

Full detection rule

Unlock this rule to view and copy it

The detection logic is included with a plan. Everything else — context, mappings and implementation details — stays free on this page.

Sign in for 3 free unlocks

Signing in gives you 3 unlocks to spend on any rule in the library. No card, and they do not expire.

Also included

Unlocked rules convert on this page — to Splunk SPL or Splunk — Raw Index SPL or Microsoft Sentinel KQL or Microsoft Sentinel ASIM ASIM KQL or Microsoft Defender XDR KQL or Elastic Security KQL or Elastic Security Lucene or Elastic Security ES|QL or CrowdStrike Falcon CQL or SentinelOne PowerQuery or Palo Alto Cortex XDR XQL or Carbon Black Cloud Platform Search or Carbon Black EDR Process Search or Google Security Operations UDM Search or IBM QRadar AQL or Sumo Logic Cloud SIEM Rules expression or Rapid7 InsightIDR LEQL or Graylog Search or OpenSearch Lucene or OpenSearch PPL PPL or Grafana Loki LogQL or SQLite SQL or Zircolite SQLite — with the log-source profile the engine picked, the field map it used, and everything it could not express. Converting a rule you have unlocked costs no further credit.

See it run on a free rule →Convert your own rule →