Suspicious AiTM Phishing Kit Session Validation Endpoint via Proxy

ATT&CK techniques

Cred Access → Collection

Recon
Resource Dev
Initial Access
Execution
Persistence
Priv Esc
Defense Evasion
Cred Access
Discovery
Lateral Movement
Collection
- T1557Adversary-in-the-Middle
C2
Exfiltration
Impact

What it detects

This rule detects web requests to reverse-proxy adversary-in-the-middle phishing kit endpoints, specifically the check_response handler carrying a session_id parameter alongside kit paths such as api/login, 2fa, sms and tap. It is associated with the Operation Fake KickOff campaign that abused recruiters and SaaS services to harvest corporate credentials and relay multi-factor authentication tokens. Detecting these structured kit paths surfaces live credential and MFA session theft.

Reporting behind it

Related detections9 linkedT1557 — drag to rearrange

Suspicious Tycoon Phishing-as-a-Service Credential Exfiltration Path (via proxy)

Suspicious AWS AiTM Phishing Kit Endpoint Access via Proxy

Malicious Evilginx AiTM Phishing Proxy Default TLS Certificate

Malicious Tycoon 2FA AiTM Phishing WebSocket Channel

Suspicious Firefox Enterprise Root Certificate Trust Enabled

Malicious Root Certificate Installed via certutil addstore for AiTM Interception

Suspicious Code of Conduct Phishing Email From cocinternal.com Sender (via m365)

Suspicious Entra Sign-In With Axios Automation User-Agent via AiTM Token Replay (via azure)

Suspicious OfficeHome Sign-In With Axios User Agent via Tycoon 2FA Proxy

Suspicious AiTM Phishing Kit Session Validation Endpoint via Proxy

Pivot detection · T1557 · 9 related

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

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