Sigma Rules
21 rules found
Azure Login Bypassing Conditional Access Policies
Detects a successful login to the Microsoft Intune Company Portal which could allow bypassing Conditional Access Policies and InTune device trust using a tool like TokenSmith.
Disabling Multi Factor Authentication
Detects disabling of Multi Factor Authentication.
New Federated Domain Added
Detects the addition of a new Federated Domain.
Suspicious Email Delivered In Microsoft 365
Detects instances where an email, identified as malicious or suspicious by the Microsoft Defender for Office 365 (formerly ATP) engine, was delivered to a user's Inbox or Junk folder. It might indicate that a potential threat, such as a spearphishing attachment or links, has bypassed initial blocking mechanisms and reached an end-user, requiring further investigation and potential remediation.
New Federated Domain Added - Exchange
Detects the addition of a new Federated Domain.
Activity from Suspicious IP Addresses
Detects when a Microsoft Cloud App Security reported users were active from an IP address identified as risky by Microsoft Threat Intelligence. These IP addresses are involved in malicious activities, such as Botnet C&C, and may indicate compromised account.
Activity Performed by Terminated User
Detects when a Microsoft Cloud App Security reported for users whose account were terminated in Azure AD, but still perform activities in other platforms such as AWS or Salesforce. This is especially relevant for users who use another account to manage resources, since these accounts are often not terminated when a user leaves the company.
Activity from Anonymous IP Addresses
Detects when a Microsoft Cloud App Security reported when users were active from an IP address that has been identified as an anonymous proxy IP address.
Activity from Infrequent Country
Detects when a Microsoft Cloud App Security reported when an activity occurs from a location that wasn't recently or never visited by any user in the organization.
Data Exfiltration to Unsanctioned Apps
Detects when a Microsoft Cloud App Security reported when a user or IP address uses an app that is not sanctioned to perform an activity that resembles an attempt to exfiltrate information from your organization.
Microsoft 365 - Impossible Travel Activity
Detects when a Microsoft Cloud App Security reported a risky sign-in attempt due to a login associated with an impossible travel.
Logon from a Risky IP Address
Detects when a Microsoft Cloud App Security reported when a user signs into your sanctioned apps from a risky IP address.
Microsoft 365 - Potential Ransomware Activity
Detects when a Microsoft Cloud App Security reported when a user uploads files to the cloud that might be infected with ransomware.
PST Export Alert Using eDiscovery Alert
Alert on when a user has performed an eDiscovery search or exported a PST file from the search. This PST file usually has sensitive information including email body content
PST Export Alert Using New-ComplianceSearchAction
Alert when a user has performed an export to a search using 'New-ComplianceSearchAction' with the '-Export' flag. This detection will detect PST export even if the 'eDiscovery search or exported' alert is disabled in the O365.This rule will apply to ExchangePowerShell usage and from the cloud.
Suspicious Inbox Forwarding
Detects when a Microsoft Cloud App Security reported suspicious email forwarding rules, for example, if a user created an inbox rule that forwards a copy of all emails to an external address.
Suspicious OAuth App File Download Activities
Detects when a Microsoft Cloud App Security reported when an app downloads multiple files from Microsoft SharePoint or Microsoft OneDrive in a manner that is unusual for the user.
Microsoft 365 - Unusual Volume of File Deletion
Detects when a Microsoft Cloud App Security reported a user has deleted a unusual a large volume of files.
Microsoft 365 - User Restricted from Sending Email
Detects when a Security Compliance Center reported a user who exceeded sending limits of the service policies and because of this has been restricted from sending email.
Mail Forwarding/Redirecting Activity In O365
Detects email forwarding or redirecting activity in O365 Audit logs.
Inbox Rules Creation Or Update Activity in O365
Detects inbox rule creation or update via O365 Audit logs, a technique commonly observed in Business Email Compromise (BEC) attacks to hide emails. The usage of inbox rules can be a sign of a compromised mailbox, where an attacker is attempting to evade detections by suppressing or redirecting incoming emails. Analysts should review these rules in context, validate whether they reflect normal user behavior, and correlate with other indicators such as unusual login activity or recent mailbox rule modifications.