Suspicious OAuth Application Consent Granted High Privilege Mail Scopes (via m365)

ATT&CK techniques

Cred Access

Recon
Resource Dev
Initial Access
Execution
Persistence
Priv Esc
Defense Evasion
Cred Access
- T1528Steal Application Access Token
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact

What it detects

This rule detects OAuth application consent operations granting mailbox read write and send permissions. Financially motivated actors registered and consented malicious OAuth applications with mail.readwrite and mail.send scopes to automate mail-based fraud and exfiltration.

Reporting behind it

Related detections9 linkedT1528 — drag to rearrange

Suspicious Token Request Using Microsoft Authentication Broker Client to Obtain Primary Refresh Token (via azure)

Suspicious Salesforce Connected App OAuth Authorization from VPN Egress

Suspicious M365 Device Code Authentication Flow via m365

Possible Illicit Consent Grant to OAuth Application via Azure AD

Suspicious Device Code Authentication via Microsoft Authentication Broker

Suspicious OAuth Device Code Sign-In to Authentication Broker via Tycoon 2FA

Suspicious OAuth Sign-In Using Visual Studio Code Client and Auth Broker

Suspicious OAuth Application Consent in Microsoft Entra

Malicious OAuth Application Granted Full Mailbox and EWS Permissions (via m365)

Suspicious OAuth Application Consent Granted High Privilege Mail Scopes (via m365)

Pivot detection · T1528 · 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 →