Detects successful Microsoft 365 portal logins from rare locations. Rare locations are defined as locations that are not commonly associated with the user's account. This behavior may indicate an adversary attempting to access a Microsoft 365 account from an unusual location or behind a VPN.

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Detects successful Microsoft 365 portal logins from impossible travel locations. Impossible travel locations are defined as two different countries within a short time frame. This behavior may indicate an adversary attempting to access a Microsoft 365 account from a compromised account or a malicious actor attempting to access a Microsoft 365 account from a different location.

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In Microsoft Entra ID, permissions to manage resources are assigned using roles. The Global Administrator / Company Administrator is a role that enables users to have access to all administrative features in Entra ID and services that use Entra ID identities like the Microsoft 365 Defender portal, the Microsoft 365 compliance center, Exchange, SharePoint Online, and Skype for Business Online. Adversaries can add users as Global Administrators to maintain access and manage all subscriptions and their settings and resources.

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Identifies an Microsoft 365 illicit consent grant request on-behalf-of a registered Entra ID application. Adversaries may create and register an application in Microsoft Entra ID for the purpose of requesting user consent to access resources in Microsoft 365. This is accomplished by tricking a user into granting consent to the application, typically via a pre-made phishing URL. This establishes an OAuth grant that allows the malicious client applocation to access resources in Microsoft 365 on-behalf-of the user.

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Detects potentially suspicious OAuth authorization activity in Microsoft 365 where the Visual Studio Code first-party application (client_id = aebc6443-996d-45c2-90f0-388ff96faa56) is used to request access to Microsoft Graph resources. While this client ID is legitimately used by Visual Studio Code, threat actors have been observed abusing it in phishing campaigns to make OAuth requests appear trustworthy. These attacks rely on redirect URIs such as VSCode Insiders redirect location, prompting victims to return an OAuth authorization code that can be exchanged for access tokens. This rule may help identify unauthorized use of the VS Code OAuth flow as part of social engineering or credential phishing activity.

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Identifies a Microsoft 365 audit log generated for Threat Intelligence signals by Microsoft Defender for Office 365. Signals generated may relate to services such as Exchange Online, SharePoint Online, OneDrive for Business and others.

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Detects a burst of Microsoft 365 user account lockouts within a short 5-minute window. A high number of IdsLocked login errors across multiple user accounts may indicate brute-force attempts for the same users resulting in lockouts.

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Identifies brute-force authentication activity targeting Microsoft 365 user accounts using failed sign-in patterns that match password spraying, credential stuffing, or password guessing behavior. Adversaries may attempt brute-force authentication with credentials obtained from previous breaches, leaks, marketplaces or guessable passwords.

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Identifies sign-ins on behalf of a principal user to the Microsoft Graph API from multiple IPs using the Microsoft Authentication Broker or Visual Studio Code application. This behavior may indicate an adversary using a phished OAuth refresh token.

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This rule correlate Azure or Office 356 mail successful sign-in events with network security alerts by source.ip. Adversaries may trigger some network security alerts such as reputation or other anomalies before accessing cloud resources.

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Identifies potential enumeration or password spraying activity using TeamFiltration tool. TeamFiltration is an open-source enumeration, password spraying and exfiltration tool designed for Entra ID and Microsoft 365. Adversaries are known to use TeamFiltration in-the-wild to enumerate users, groups, and roles, as well as to perform password spraying attacks against Microsoft Entra ID and Microsoft 365 accounts. This rule detects the use of TeamFiltration by monitoring for specific user-agent strings associated with the tool in Azure and Microsoft 365 logs.

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Identifies an excessive number of Microsoft 365 mailbox items accessed by a user either via aggregated counts or throttling. Microsoft audits mailbox access via the MailItemsAccessed event, which is triggered when a user accesses mailbox items. If more than 1000 mailbox items are accessed within a 24-hour period, it is then throttled. Excessive mailbox access may indicate an adversary attempting to exfiltrate sensitive information or perform reconnaissance on a target's mailbox. This rule detects both the throttled and unthrottled events with a high threshold.

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Identifies suspicious Microsoft 365 mail access by ClientAppId. This rule detects when a user accesses their mailbox using a client application that is not typically used by the user, which may indicate potential compromise or unauthorized access attempts. Adversaries may use custom or third-party applications to access mailboxes, bypassing standard security controls. First-party Microsoft applications are also abused after OAuth tokens are compromised, allowing adversaries to access mailboxes without raising suspicion.

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Identifies potential enumeration activity using AzureHound, SharpHound, or BloodHound across Microsoft cloud services. These tools are often used by red teamers and adversaries to map users, groups, roles, applications, and access relationships within Microsoft Entra ID (Azure AD) and Microsoft 365.

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Identifies when a user creates a new inbox rule in Microsoft 365 that deletes or moves emails containing suspicious keywords. Adversaries who have compromised accounts often create inbox rules to hide alerts, security notifications, or other sensitive messages by automatically deleting them or moving them to obscure folders. Common destinations include Deleted Items, Junk Email, RSS Feeds, and RSS Subscriptions. This is a New Terms rule that triggers only when the user principal name and associated source IP address have not been observed performing this activity in the past 14 days.

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Identifies the assignment of rights to access content from another mailbox. An adversary may use the compromised account to send messages to other accounts in the network of the target organization while creating inbox rules, so messages can evade spam/phishing detection mechanisms.

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Identifies attempts to register a new device in Microsoft Entra ID after OAuth authentication with authorization code grant. Adversaries may use OAuth phishing techniques to obtain an OAuth authorization code, which can then be exchanged for access and refresh tokens. This rule detects a sequence of events where a user principal authenticates via OAuth, followed by a device registration event, indicating potential misuse of the OAuth flow to establish persistence or access resources.

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