huntrule

Pulse Connect Secure web exploitation attempts for CVE-2021-22893

Detects web requests to Pulse Connect Secure with URI query patterns consistent with CVE-2021-22893 exploitation attempts.

FreeReviewedSigma · High · v5
Category
webserver
Author
Sittikorn S (SigmaHQ), DRL 1.1
Published
2021-06-29
Updated
2026-07-31
AnalysisDetection

ATT&CK techniques

Initial Access

  1. Recon

  2. Resource Dev

  3. Initial Access

  4. Execution

  5. Persistence

  6. Priv Esc

  7. Defense Evasion

  8. Cred Access

  9. Discovery

  10. Lateral Movement

  11. Collection

  12. C2

  13. Exfiltration

  14. Impact

What it detects

This rule identifies likely exploitation activity against Pulse Connect Secure by matching HTTP requests whose query strings include Pulse-specific application paths and RCE-relevant parameter patterns. Attackers may probe or execute the vulnerable functionality by sending crafted requests containing tokens, CGI parameter indicators, and related fields. Telemetry required includes webserver HTTP request metadata, specifically cs-uri-query content in inbound requests.

Reporting behind it

Related detections9 linkedT1190 — drag to rearrange
Malicious Node.js Process Spawning Unix Shell or Network Client
Malicious SharePoint ToolShell Exploitation via ToolPane Endpoint
Malicious Exchange Mailbox Export to ASPX via New-MailboxExportRequest
Suspicious Shell Spawned by ActiveMQ Java Process
Cleo Autorun Exploitation via Healthcheck File Drop
Suspicious SharePoint Worker Process Spawning Command Interpreter via ToolShell
Malicious IIS Worker Process Spawning Command Shell Reconnaissance
Potential StyleSmuggler (CVE-2026-75650) Exploitation Attempt - Magento GraphQL Styles Parameter (via webserver)
Cisco IOS XE Configuration Change by Web UI WSMA User
Pulse Connect Secure web exploitation attempts for CVE-2021-22893
Pivot detection · T1190 · 9 related

Changelog

v5
  1. v5
    Candidate ingested via manual entry.2026-07-31
  2. v4
    Candidate ingested via manual entry.2026-07-31
  3. v3
    Candidate ingested via manual entry.2026-07-31
  4. v2
    Candidate ingested via manual entry.2026-07-31
  5. v1
    No changelog recorded for this version.2026-07-30

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