Possible AiTM Phishing Sign-On Evaluation Denied by Okta FastPass

ATT&CK techniques

Initial Access → Collection

Recon
Resource Dev
Initial Access
- T1566.002Spearphishing Link
Execution
Persistence
Priv Esc
Defense Evasion
Cred Access
- T1557Adversary-in-the-Middle
Discovery
Lateral Movement
Collection
- T1557Adversary-in-the-Middle
C2
Exfiltration
Impact

What it detects

This rule detects Okta sign-on policy evaluations that are challenged or denied where the network reputation flags a phishing or proxy origin, matching FastPass anti-phishing rejections. In this campaign an adversary-in-the-middle proxy relayed authentication and Okta FastPass declined the phishing attempt during policy evaluation. Clusters of such denials indicate active AiTM targeting of user credentials and session tokens.

Reporting behind it

Related detections9 linkedT1566.002 — drag to rearrange

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Suspicious OAuth Application Consent Grant via Azure Audit Logs

Suspicious OWA Proxy User-Agent Indicating Mailbox Access

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 Anonymous Sharing Link Creation in SharePoint or OneDrive via M365 Audit

Possible AiTM Phishing Sign-On Evaluation Denied by Okta FastPass

Pivot detection · T1566.002 · 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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