Suspicious Malformed DONNECT HTTP Method in Proxy Logs via Proxy

ATT&CK techniques

C2

Recon
Resource Dev
Initial Access
Execution
Persistence
Priv Esc
Defense Evasion
Cred Access
Discovery
Lateral Movement
Collection
C2
- T1071.001Web Protocols
Exfiltration
Impact

What it detects

This rule detects the malformed DONNECT HTTP verb observed in REF5961 command and control traffic which is a typographical artifact of the tooling rather than a valid HTTP method. Legitimate clients never emit DONNECT so its presence in proxy logs is a strong indicator of the intrusion set beaconing through a proxy.

Reporting behind it

Related detections9 linkedT1071.001 — drag to rearrange

Suspicious BLOODALCHEMY Command and Control URI Pattern via Proxy

Malicious MIMICRAT C2 HTTP Request Pattern (via proxy)

Suspicious Contagious Interview Exfiltration via Axios Upload User Agent

Malicious NANOREMOTE C2 Beacon by User-Agent

Suspicious Network Connection from fsutil or Defender Client via network_connection

Suspicious Data Exfiltration Channel to Telegram or Discord via dns_query

Malicious C2 Domain Beacon To Akamaitechnologies Masquerade via DPRK Python Intrusion

Malicious WmRAT C2 Beacon via excerorderslist Endpoint (via proxy)

Malicious DarkGate C2 Communication via Synapse User-Agent (via proxy)

Suspicious Malformed DONNECT HTTP Method in Proxy Logs via Proxy

Pivot detection · T1071.001 · 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 →