Detections

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

37 detections

Detects anomalous, high-volume account enumeration against the Microsoft Self-Service Password Reset (SSPR) endpoint from a single source IP. The rule identifies a pattern of mixed response codes, specifically interleaving '50034' (Account does not exist) with successful or other outcomes, which indicates the use of automated tools to validate the existence of corporate accounts via response differentiation.
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Ankit Mehta@Secvyn
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SlimKQL 2026
1 month ago
409
Detects high-volume account enumeration activity associated with the TeamFiltration tool, characterized by the use of legacy Microsoft Teams desktop client User-Agent strings (specific versions of Teams, Electron, and Chrome) within a short time window.
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Arnold Chan@slaz
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Hunters
1 month ago
003
This rule detects high-frequency API endpoint access originating from a single source IP address within a one-minute window, where the User-Agent does not match common browser strings. This behavior is indicative of automated scanning, scraping, or brute-force enumeration of API resources by non-browser clients.
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Ankit Mehta@Secvyn
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Detections.ai Community
28 days ago
001
Detects high-volume account enumeration activity associated with the TeamFiltration tool, characterized by the use of legacy Microsoft Teams desktop client User-Agent strings (specific versions of Teams, Electron, and Chrome) within a short time window.
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Arnold Chan@slaz
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Detection & Hunting Community
1 month ago
101
Detects high-volume account enumeration activity associated with the TeamFiltration tool, characterized by the use of legacy Microsoft Teams desktop client User-Agent strings (specific versions of Teams, Electron, and Chrome) within a short time window.
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Arnold Chan@slaz
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Detections.ai Community
1 month ago
001
Detects Microsoft Graph API requests targeting user information endpoints (/v1.0/users or /v1.0/me) using specific search filters associated with payroll or human resources and identified by the Axios HTTP client User-Agent string. This pattern is consistent with reconnaissance activities.
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Ibrahim Saud@tektrix
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Detections.ai Community
1 month ago
004
Detects high-volume account existence checks targeting the Microsoft Teams API. The rule identifies anomalous authentication attempts characterized by the use of outdated Electron/Chrome user-agent strings associated with the TeamFiltration tool, specifically targeting the Microsoft Teams API AppId (1fec8e78-bce4-4aaf-ab1b-5451cc387264).
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Ankit Mehta@Secvyn
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Detection & Hunting Community
1 month ago
102
Detects potential account compromise by identifying a specific sequence of behavior: reconnaissance of sensitive users (HR/Payroll) via Microsoft Graph API calls, followed by the creation of inbox rules (e.g., forwarding) by the same user account within a 12-hour window.
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Ibrahim Saud@tektrix
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Detections.ai Community
1 month ago
003
Detects reconnaissance activity targeting sensitive personnel groups (payroll, HR, finance) via Microsoft Graph API. The rule identifies suspicious URI patterns combined with the use of the 'axios' User-Agent library, potentially indicating automated enumeration by an adversary to map high-value targets for future business email compromise or credential theft.
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Ibrahim Saud@tektrix
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Detections.ai Community
1 month ago
103
Detects anomalous, high-volume account enumeration against the Microsoft Self-Service Password Reset (SSPR) endpoint from a single source IP. The rule identifies a pattern of mixed response codes, specifically interleaving '50034' (Account does not exist) with successful or other outcomes, which indicates the use of automated tools to validate the existence of corporate accounts via response differentiation.
avatar
Ankit Mehta@Secvyn
avatar
Detection & Hunting Community
1 month ago
001
Detects anomalous, high-volume account enumeration against the Microsoft Self-Service Password Reset (SSPR) endpoint from a single source IP. The rule identifies a pattern of mixed response codes, specifically interleaving '50034' (Account does not exist) with successful or other outcomes, which indicates the use of automated tools to validate the existence of corporate accounts via response differentiation.
avatar
Ankit Mehta@Secvyn
avatar
SlimKQL
1 month ago
101
Detects high-volume account enumeration activity associated with the TeamFiltration tool, characterized by the use of legacy Microsoft Teams desktop client User-Agent strings (specific versions of Teams, Electron, and Chrome) within a short time window.
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Arnold Chan@slaz
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Midnight Slayer
1 month ago
000
Detects high-volume account existence checks targeting the Microsoft Teams API. The rule identifies anomalous authentication attempts characterized by the use of outdated Electron/Chrome user-agent strings associated with the TeamFiltration tool, specifically targeting the Microsoft Teams API AppId (1fec8e78-bce4-4aaf-ab1b-5451cc387264).
avatar
Ankit Mehta@Secvyn
avatar
SlimKQL
1 month ago
001
Detects anomalous, high-volume account enumeration against the Microsoft Self-Service Password Reset (SSPR) endpoint from a single source IP. The rule identifies a pattern of mixed response codes, specifically interleaving '50034' (Account does not exist) with successful or other outcomes, which indicates the use of automated tools to validate the existence of corporate accounts via response differentiation.
avatar
Ankit Mehta@Secvyn
avatar
Detections.ai Community
1 month ago
000
Detects high-volume account existence checks targeting the Microsoft Teams API. The rule identifies anomalous authentication attempts characterized by the use of outdated Electron/Chrome user-agent strings associated with the TeamFiltration tool, specifically targeting the Microsoft Teams API AppId (1fec8e78-bce4-4aaf-ab1b-5451cc387264).
avatar
Ankit Mehta@Secvyn
avatar
Hunters
1 month ago
000
Detects high-volume account existence checks targeting the Microsoft Teams API. The rule identifies anomalous authentication attempts characterized by the use of outdated Electron/Chrome user-agent strings associated with the TeamFiltration tool, specifically targeting the Microsoft Teams API AppId (1fec8e78-bce4-4aaf-ab1b-5451cc387264).
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Ankit Mehta@Secvyn
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Detections.ai Community
1 month ago
000
This rule detects high-frequency account and email address enumeration attempts. It monitors syslog data for SMTP commands such as VRFY, EXPN, or RCPT TO, and analyzes Microsoft Entra ID (SigninLogs) for authentication failures specifically associated with error code 50034 (user not found). Both behaviors are indicative of an adversary attempting to validate user identities within an environment, often as a precursor to targeted phishing or brute-force attacks.
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Arnold Chan@slaz
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Hunters
2 months ago
005
This rule detects high-frequency account and email address enumeration attempts. It monitors syslog data for SMTP commands such as VRFY, EXPN, or RCPT TO, and analyzes Microsoft Entra ID (SigninLogs) for authentication failures specifically associated with error code 50034 (user not found). Both behaviors are indicative of an adversary attempting to validate user identities within an environment, often as a precursor to targeted phishing or brute-force attacks.
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Arnold Chan@slaz
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Midnight Slayer
2 months ago
006
Detects the use of the "Get-ADComputer" cmdlet in order to identify systems which are configured for unconstrained delegation.
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SigmaHQ Detections@sigmaHQ
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SigmaHQ
2 months ago
002
This rule detects high-frequency account and email address enumeration attempts. It monitors syslog data for SMTP commands such as VRFY, EXPN, or RCPT TO, and analyzes Microsoft Entra ID (SigninLogs) for authentication failures specifically associated with error code 50034 (user not found). Both behaviors are indicative of an adversary attempting to validate user identities within an environment, often as a precursor to targeted phishing or brute-force attacks.
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Arnold Chan@slaz
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Detections.ai Community
2 months ago
107
Detects potential username enumeration attempts against Microsoft Entra ID (Azure AD) by monitoring for the 'AADSTS50034' error code, which occurs when a sign-in attempt is made with a username that does not exist in the directory. This behavior is often associated with adversary reconnaissance to identify valid user accounts.
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Duo Tech@duotech
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Detections.ai Community
4 months ago
12025
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