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.

Read More

Identifies the occurrence of files uploaded to OneDrive being detected as Malware by the file scanning engine. Attackers can use File Sharing and Organization Repositories to spread laterally within the company and amplify their access. Users can inadvertently share these files without knowing their maliciousness, giving adversaries an opportunity to gain initial access to other endpoints in the environment.

Read More

Identifies when an excessive number of files are downloaded from OneDrive or SharePoint by an authorized user or application in a short period of time. This may indicate a potential data exfiltration event, especially if the downloads are performed using OAuth authentication which could suggest an OAuth phishing attack such as Device Code Authentication phishing.

Read More

Identifies file downloads or access from OneDrive or SharePoint using PowerShell-based user agents. Adversaries may use native PowerShell cmdlets like Invoke-WebRequest or Invoke-RestMethod with Microsoft Graph API to exfiltrate data after compromising OAuth tokens via device code phishing or other credential theft techniques. This rule detects both direct PowerShell access and PnP PowerShell module usage for file operations. FileAccessed events are included to detect adversaries reading file content via API and saving locally, bypassing traditional download methods. Normal users access SharePoint/OneDrive via browsers or sync clients, making PowerShell-based file access inherently suspicious.

Read More