Entra ID Sharepoint or OneDrive Accessed by Unusual Client

Description

Identifies when an application accesses SharePoint Online or OneDrive for Business for the first time in the tenant within a specified timeframe. This detects successful OAuth phishing campaigns, illicit consent grants, or compromised third-party applications gaining initial access to file storage. Adversaries often use malicious OAuth applications or phishing techniques to gain consent from users, allowing persistent access to organizational data repositories without traditional credential theft.

Detection logic

Its licence does not clear it for publishing here

Sunturai publishes a detection's own text where the licence it arrived under has been reviewed and permits it, and Elastic License 2.0 has not. The query as its source wrote it, its canonical form and the hash that pins this revision are in the workspace record.

Detection requirements

Platform: Containers ESXi IaaS Identity Provider Linux macOS Network Devices Office Suite SaaS Windows
The rule states no platform. This is derived from the 4 ATT&CK techniques it maps to.
Log source category: event_index

Known benign triggers

Developers testing new applications or OAuth flows in non-production tenants may generate alerts during development cycles.
New legitimate applications or integrations recently deployed in the environment may trigger this detection during initial setup or rollout phases.
Third-party SaaS applications with SharePoint integration may appear as new app IDs when users first authorize access.

References

Links the source published beside this detection. Reference is the link the source wrote, unmodified. Class is decided by this catalogue from the host and path, not stated by the source. Cited by counts published detections citing the same resource, including this one, and the sources beneath it count the repositories this catalogue ingests, which is not the same as independent research.
Reference	Class	Cited by
github.com/merill/microsoft-info/blob/main/_info/MicrosoftApps.json	Tool	Only this detection cites it
learn.microsoft.com/en-us/entra/identity/enterprise-apps/manage-consent-requests	Product documentation	Only this detection cites it
www.microsoft.com/en-us/security/blog/2022/09/22/malicious-oauth-applications-used-to-compromise-email-servers-and-spread-spam/	Threat report	8from 2 sources
www.volexity.com/blog/2025/04/22/phishing-for-codes-russian-threat-actors-target-microsoft-365-oauth-workflows/	Threat report	19

Detection rules

Entra ID Sharepoint or OneDrive Accessed by Unusual Client

Description

Detection logic

Detection requirements

Known benign triggers

MITRE ATT&CK mappings

References

From the source

Licence

Authorship

Detection rules