Detections

Explore public detection logic contributed by the community across SIEM and rule languages.

3,142 detections

Detects anomalous Microsoft 365 session behavior where a single SessionId persists across multiple sign-ins that originate from rotating IP addresses and ASNs. The detection identifies signs of potential session token theft, specifically looking for traffic matching the Microsoft Outlook client app signature paired with non-standard user agents (e.g., Firefox or Python requests) that exhibit recurring sign-in attempts at approximately 8-hour intervals, which is typical for automated token refresh cycles.
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Ibrahim Saud@tektrix
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Detections.ai Community
1 month ago
001
Detects suspicious O365 'MailItemsAccessed' activity using a specific OAuth application (AppId c999ed3e-27ae-4cb3-b3a2-46b056af63d3) and ClientId (5d661950-3475-41cd-a2c3-d671a3162bc1) with an 'Bind' operation type. This pattern is often associated with unauthorized email access across multiple tenant accounts. The rule triggers when at least 5 events are detected across 2 or more distinct tenant accounts within a 1-minute window, using a specific Firefox user agent.
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Ibrahim Saud@tektrix
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Detections.ai Community
1 month ago
001
Detects anomalous sign-in attempts to the OfficeHome application where an OAuth 90014 error (nonce mismatch/invalid) is returned. The detection specifically monitors for requests originating from mobile browsers on Windows 10 user agents, which is indicative of potential adversary-in-the-middle (AiTM) phishing activity attempting to bypass or intercept authentication tokens.
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Ibrahim Saud@tektrix
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Detections.ai Community
1 month ago
101
Detects anomalous sign-in activity where a single Microsoft 365 or Entra ID user account successfully authenticates from multiple distinct residential or mobile-carrier ASNs within a 24-hour window. This behavior is highly indicative of an adversary replaying stolen session tokens (AiTM) through rotating residential proxy networks to blend into legitimate user traffic and circumvent location-based or datacenter IP-based access restrictions.
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Ibrahim Saud@tektrix
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Detections.ai Community
1 month ago
001
Detects the creation or modification of O365 inbox rules designed to move incoming emails to the 'Deleted Items' folder, delete messages, or mark them as read. This behavior is a common indicator of an adversary attempting to hide phishing lures, security alerts, or C2 communications within a compromised mailbox.
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Ibrahim Saud@tektrix
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Detections.ai Community
1 month ago
001
Detects anomalous 'Bind' operations in Microsoft 365 Exchange Online audit logs where the user-agent string includes 'Firefox/131.0' and 'Client=REST' while using specific Microsoft Outlook ClientAppId and APIId parameters. This pattern has been observed in automated, cross-tenant mailbox exfiltration campaigns targeting sensitive payroll and financial documentation.
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Ibrahim Saud@tektrix
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Detections.ai Community
1 month ago
001
Detects phishing emails that impersonate Adobe Acrobat Sign or DocuSign using invoice or RFP-themed lures. The rule identifies suspicious emails by checking for brand-related keywords in the subject and display name, identifying links that do not lead to legitimate signing domains, and identifying senders that are impersonating a brand or are newly seen in the environment.
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Arnold Chan@slaz
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Hunters
1 month ago
301
Detects phishing emails that impersonate Adobe Acrobat Sign or DocuSign using invoice or RFP-themed lures. The rule identifies suspicious emails by checking for brand-related keywords in the subject and display name, identifying links that do not lead to legitimate signing domains, and identifying senders that are impersonating a brand or are newly seen in the environment.
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Arnold Chan@slaz
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Midnight Slayer
1 month ago
101
Detects phishing emails that impersonate Adobe Acrobat Sign or DocuSign using invoice or RFP-themed lures. The rule identifies suspicious emails by checking for brand-related keywords in the subject and display name, identifying links that do not lead to legitimate signing domains, and identifying senders that are impersonating a brand or are newly seen in the environment.
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Arnold Chan@slaz
Defender - KQL
1 month ago
001
Detects phishing emails that impersonate Adobe Acrobat Sign or DocuSign using invoice or RFP-themed lures. The rule identifies suspicious emails by checking for brand-related keywords in the subject and display name, identifying links that do not lead to legitimate signing domains, and identifying senders that are impersonating a brand or are newly seen in the environment.
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Arnold Chan@slaz
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Detection & Hunting Community
1 month ago
001
This rule detects high-confidence phishing emails that were delivered to either the Inbox or Junk folder. It explicitly filters out messages that have been explicitly allowed by organization-level policies, user-level actions, or specific safe-sender bypass mechanisms, ensuring the alert focuses on malicious emails that bypassed standard security filters without an authorized exception.
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Arnold Chan@slaz
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Detection & Hunting Community
1 month ago
001
Detects a suspected EvilTokens attack sequence where a user clicks a phishing URL and subsequently initiates a browser session to the Microsoft device-code authorization page (devicelogin) within 15 minutes, with the phishing lure domain appearing in the browser context.
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Arnold Chan@slaz
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Midnight Slayer
1 month ago
001
Detects potentially malicious OAuth device code sign-ins by identifying sign-in events that exhibit anomalous characteristics, such as atypical geographic locations, rare client-application combinations, unmanaged/noncompliant device status, or elevated risk signals associated with the account. This detection helps identify account compromise or malicious OAuth consent activity often associated with 'EvilTokens' or device-code phishing attacks.
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Arnold Chan@slaz
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Midnight Slayer
1 month ago
101
Detects anomalous outbound email activity from an account that recently performed an OAuth device code sign-in characterized by elevated risk levels. The rule identifies potential token abuse by looking for a high volume of emails with either a significant percentage of external recipients or patterns indicative of bulk mailing, common in phishing campaigns that leverage compromised identities (e.g., EvilTokens).
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Arnold Chan@slaz
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Hunters
1 month ago
101
Detects anomalous outbound email activity from an account that recently performed an OAuth device code sign-in characterized by elevated risk levels. The rule identifies potential token abuse by looking for a high volume of emails with either a significant percentage of external recipients or patterns indicative of bulk mailing, common in phishing campaigns that leverage compromised identities (e.g., EvilTokens).
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Arnold Chan@slaz
Defender - KQL
1 month ago
001
Detects the creation of an email inbox rule that includes both a concealment/deletion action and an external forwarding destination, occurring within 4 hours of a high-risk or compromised device-code authentication event. This pattern is indicative of account takeover where an attacker establishes persistence and exfiltration while hiding their activity.
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Arnold Chan@slaz
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Detection & Hunting Community
1 month ago
001
Detects the creation of an email inbox rule that includes both a concealment/deletion action and an external forwarding destination, occurring within 4 hours of a high-risk or compromised device-code authentication event. This pattern is indicative of account takeover where an attacker establishes persistence and exfiltration while hiding their activity.
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Arnold Chan@slaz
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Midnight Slayer
1 month ago
001
Detects the creation of an email inbox rule that includes both a concealment/deletion action and an external forwarding destination, occurring within 4 hours of a high-risk or compromised device-code authentication event. This pattern is indicative of account takeover where an attacker establishes persistence and exfiltration while hiding their activity.
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Arnold Chan@slaz
Defender - KQL
1 month ago
001
Detects the scripted, non-human-paced registration of a rogue external authentication method by monitoring a sequence of specific Azure Audit Log operations (Add application, Add service principal, Add delegated permission grant) occurring within 60 seconds of each other by the same actor. The detection is further corroborated by analyzing Microsoft Graph Activity Logs for associated Python requests to specific Graph API URIs.
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Ankit Mehta@Secvyn
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Hunters
1 month ago
601
Detects the scripted, non-human-paced registration of a rogue external authentication method by monitoring a sequence of specific Azure Audit Log operations (Add application, Add service principal, Add delegated permission grant) occurring within 60 seconds of each other by the same actor. The detection is further corroborated by analyzing Microsoft Graph Activity Logs for associated Python requests to specific Graph API URIs.
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Ankit Mehta@Secvyn
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Detection & Hunting Community
1 month ago
101
This rule detects potential security configuration tampering by correlating the modification of a Conditional Access policy (e.g., changing users or conditions) with the registration of a new external authentication method configuration by the same user within a 3-hour window. This behavior may indicate an attacker attempting to establish persistence or facilitate bypass of authentication requirements by modifying CA policies and adding a rogue authentication method.
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Ankit Mehta@Secvyn
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Detections.ai Community
1 month ago
101
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