Possible Adversary-in-the-Middle Proxy Login via Crafted URL Parameters

ATT&CK techniques

Cred Access → Collection

Recon
Resource Dev
Initial Access
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 HTTP requests carrying the qrc and login_hint URL parameters used by an adversary-in-the-middle proxy that relays victims to a spoofed Outlook login page. This tradecraft was observed in an HTML smuggling campaign that harvested Microsoft 365 credentials and session tokens. AiTM session theft bypasses multi-factor authentication and enables account takeover.

Reporting behind it

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Malicious Tycoon 2FA AiTM Phishing WebSocket Channel

Possible Adversary-in-the-Middle Proxy Login via Crafted URL Parameters

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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