Detections
Explore public detection logic contributed by the community across SIEM and rule languages.
3,141 detections
Filters
Last updated
All Time
Detection languages
2,292
246
196
179
104
Contributors
738
670
569
284
148
Categories
1,163
747
693
623
440
Platforms
39,926
7,251
6,535
3,864
3,632
3,141
Products / Services
2,849
742
268
187
182
MITRE Techniques
871
856
778
768
738
CVEs
13
5
2
1
1
IDS Classtypes
3
2
2
2
1
IDS Protocols
9
1
1
The following analytic identifies instances where Multi-Factor Authentication (MFA) is disabled for a user within the Office 365 environment. It leverages O365 audit logs, specifically focusing on events related to MFA settings. Disabling MFA removes a critical security layer, making accounts more vulnerable to unauthorized access. If confirmed malicious, this activity could indicate an attacker attempting to maintain persistence or an insider threat, significantly increasing the risk of unauthorized access. Immediate investigation is required to validate the reason for disabling MFA, potentially re-enable it, and assess any other suspicious activities related to the affected account.
This analytic detects when an excessive number of files are downloaded from Office 365 by the same user over a short period of time. Office 365 may bundle these files together as a ZIP file, however each file will have its own download event. This behavior may indicate an attacker staging data for exfiltration or an insider threat removing organizational data. Additional attention should be taken with any Azure Guest (#EXT#) accounts.
This analytic identifies when a new owner is assigned to an application registration within an Azure AD and Office 365 tenant. This activity is significant because assigning a new owner to an application registration can grant significant control over the application's configuration, permissions, and behavior. If confirmed malicious, an attacker could modify the application's settings, permissions, and behavior, leading to unauthorized data access, privilege escalation, or the introduction of malicious behavior within the application's operations.
The following analytic identifies the addition of a new federated domain in an Office 365 environment. This behavior is detected by analyzing Office 365 management activity logs, specifically filtering for Workload=Exchange and Operation="Add-FederatedDomain". The addition of a new federated domain is significant as it may indicate unauthorized changes or potential compromises. If confirmed malicious, attackers could establish a backdoor, bypass security measures, or exfiltrate data, leading to data breaches and unauthorized access to sensitive information. Immediate investigation is required to review the details of the added domain and any concurrent suspicious activities.
This analytic identifies instances where tenant-wide admin consent is granted to an application within an Azure AD and Office 365 tenant. It leverages O365 audit logs, specifically events related to the "Consent to application." operation within the AzureActiveDirectory workload, and filters for `ConsentType = "AllPrincipals"`. This activity is significant because admin consent allows applications to access data across the entire tenant, potentially exposing vast amounts of organizational data. If confirmed malicious, an attacker could gain extensive and persistent access to organizational data, leading to data exfiltration, espionage, further malicious activities, and potential compliance violations.
This analytic identifies when built-in Microsoft 365 security detections for suspicious email behaviors are triggered. These alerts often indicate that an attacker may have compromised a mailbox within the environment, leading to activities such as suspicious email sending patterns, user restrictions from sending email, suspicious email forwarding activity, or email sending limits being exceeded. Monitoring these alerts is crucial for responding to potential account compromises and malicious email activities.
This analytic identifies when a user with sufficient access to Exchange Online alters the mail flow/transport rule configuration of the organization. Transport rules are a set of rules that can be used by attackers to modify or delete emails based on specific conditions. This activity could indicate an attacker hiding or exfiltrating data by manipulating email flow.
The following analytic identifies instances where a single service principal creates more than three unique OAuth applications within a 10-minute timeframe. It leverages O365 logs from the Unified Audit Log, focusing on the 'Add service principal' operation in the Office 365 Azure Active Directory environment. This activity is significant as it may indicate a compromised or malicious service principal attempting to expand control or access within the network. If confirmed malicious, this could lead to unauthorized access and potential lateral movement within the environment, posing a significant security risk.
This rule detects the creation of new mail flow rules in Office 365 that are configured to redirect or copy emails to unauthorized or external addresses. It specifically looks for the "New-TransportRule" operation in Office 365 Management Activity logs, combined with parameters such as "BlindCopyTo", "CopyTo", or "RedirectMessageTo". Such activity can indicate potential data exfiltration, unauthorized access to sensitive information, or an attacker attempting to intercept email communications, which could lead to data breaches or information leakage.
This analytic identifies when specific Office 365 advanced security settings related to anti-phishing, safe links, safe attachments, or malware protection are altered within the Office 365 tenant. An attacker disabling these settings could reduce their risk of detection, potentially leading to unauthorized data access, data exfiltration, account compromise, or other malicious activities without leaving a detailed audit trail.
The following analytic detects instances where the inbox folder of an Office 365 mailbox is shared with all users within the tenant. It leverages Office 365 management activity events to identify when the 'Inbox' folder permissions are modified to include 'Everyone' with read rights. This activity is significant as it represents a potential security risk, allowing unauthorized access to sensitive emails. If confirmed malicious, this could lead to data breaches, exfiltration of confidential information, and further compromise through spear-phishing or other malicious activities based on the accessed email content.
This analytic leverages alerts from Microsoft Defender O365 Incidents. It aggregates and summarizes these alerts, extracting details such as destination, file name, severity, process command line, IP address, registry key, signature, description, and timestamps. The detection filters out alerts with a verdict of 'Clean' from Microsoft. It dynamically maps MITRE techniques from the alert data and assigns a risk score based on the alert's severity. This rule is designed to correlate Microsoft-provided alerts with other data for risk-based alerting, rather than detecting new activity from raw data.
The following analytic identifies instances where a single user creates more than three unique OAuth applications within a 10-minute window in the Office 365 environment. It leverages O365 logs from the Unified Audit Log, focusing on the 'Add service principal' operation in Azure Active Directory. This activity is significant as it may indicate a compromised user account or unauthorized actions, potentially leading to broader network infiltration or privilege escalation. If confirmed malicious, this behavior could allow attackers to gain persistent access, escalate privileges, or exfiltrate sensitive information.
The following analytic identifies a spike in failed authentication attempts within an Office 365 environment, indicative of a potential distributed password spraying attack. It leverages UserLoginFailed events from O365 Management Activity logs, focusing on ErrorNumber 50126. This detection is significant as it highlights attempts to bypass security controls using multiple IP addresses and user agents. If confirmed malicious, this activity could lead to unauthorized access, data breaches, privilege escalation, and lateral movement within the organization. Early detection is crucial to prevent account takeovers and mitigate subsequent threats.
The following analytic identifies when a suspicious email is detected within the Microsoft Office 365 ecosystem through the Advanced Threat Protection engine and delivered to an end user. Attackers may execute several attacks through email, any detections from built-in Office 365 capabilities should be monitored and responded to appropriately. Certain premium Office 365 capabilities such as Safe Attachment and Safe Links further enhance these detection and response functions.
This analytic identifies when a malicious file is detected within the Microsoft Office 365 ecosystem by the Advanced Threat Protection (ATP) engine. Attackers often stage and execute malicious files from within cloud environments like Office 365. Monitoring detections from built-in Office 365 capabilities, such as those enhanced by Safe Attachments and Safe Links, is crucial for identifying and responding to threats.
The following analytic detects the addition of new service principal accounts in O365 tenants. It leverages data from the `o365_management_activity` dataset, specifically monitoring for operations related to adding or creating service principals. This activity is significant because attackers can exploit service principals to gain unauthorized access and perform malicious actions within an organization's environment. If confirmed malicious, this could allow attackers to interact with APIs, access resources, and execute operations on behalf of the organization, potentially leading to data breaches or further compromise.
This analytic detects when Microsoft Office 365 Data Loss Prevention (DLP) rules have been triggered. DLP rules are configured for security, regulatory, or business compliance reasons. Detections from this analytic should be thoroughly evaluated to determine the security relevance of the underlying DLP events. The accuracy of this analytic depends on the upstream DLP configuration.
The following analytic identifies when an O365 email account sends and then hard deletes an email to an external recipient within a short period (within 1 hour). This behavior may indicate a compromised account where the threat actor is attempting to remove forensic artifacts or evidence of exfiltration activity. This behavior is often seen when threat actors want to reduce the probability of detection by the compromised account owner.
The following analytic identifies unusual authentication activity in an O365 environment, where a single user account experiences more than 8 authentication attempts using 3 or more unique application IDs and over 5 unique user agents within a short timeframe. It leverages O365 audit logs, focusing on authentication events and applying statistical thresholds. This behavior is significant as it may indicate an adversary probing for multi-factor authentication weaknesses. If confirmed malicious, it suggests a compromised account, potentially leading to unauthorized access, privilege escalation, and data exfiltration. Early detection is crucial to prevent further exploitation.
The following analytic identifies the creation of new email forwarding rules in an Office 365 environment via the UpdateInboxRules operation. It leverages Office 365 management activity events to detect rules that forward emails to external recipients by examining the OperationProperties for specific forwarding actions. This activity is significant as it may indicate unauthorized email redirection, potentially leading to data exfiltration. If confirmed malicious, attackers could intercept sensitive communications, leading to data breaches and information leakage.
Page 144 of 150