Detections

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

780 detections

Detects credential stuffing in Entra ID sign-in logs: one source IP failing against many distinct accounts within an hour, then succeeding on a small number of them.
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Arnold Chan@slaz
Defender - KQL
19 days ago
002
Detects sign-in activity originating from a known suspicious VPN/proxy IP range targeting critical Microsoft 365 applications. The rule specifically monitors for instances where multi-factor authentication (MFA) enforcement appears to be absent or failed, suggesting a potential account compromise and subsequent data access attempt via a proxy/VPN.
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Ankit Mehta@Secvyn
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SlimKQL 2026
27 days ago
22019
Detects Microsoft Entra ID (formerly Azure AD) sign-in attempts that use the specific, hardcoded User-Agent string associated with the TeamFiltration tool. This tool is frequently used for mass credential testing against Microsoft 365 environments. The detection looks for a suspicious and outdated combination of Teams, Electron, and Chrome versions that would not be present in legitimate, modern Microsoft Teams client traffic.
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Ankit Mehta@Secvyn
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SlimKQL 2026
27 days ago
6016
Detects credential stuffing in Entra ID sign-in logs: one source IP failing against many distinct accounts within an hour, then succeeding on a small number of them.
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Arnold Chan@slaz
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Detection & Hunting Community
19 days ago
001
Detects the initiation of VPN or ICA sessions on Citrix NetScaler devices where there is no record of a corresponding successful AAA (Authentication, Authorization, and Accounting) login event from the same source IP address within a one-hour lookback window. This pattern may indicate potential authentication bypass attempts, such as those associated with recent vulnerabilities in NetScaler products.
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Ibrahim Saud@tektrix
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Detections.ai Community
30 days ago
7020
This rule detects potential password spraying activity by monitoring for a single source IP address that targets multiple distinct user accounts with failed authentication attempts. It specifically identifies 'low-and-slow' patterns that may attempt to evade standard lockout thresholds, and flags cases where legacy authentication protocols are utilized, a technique commonly employed to bypass Multi-Factor Authentication (MFA).
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Ankit Mehta@Secvyn
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Detections.ai Community
1 month ago
15019
This rule monitors Linux system authentication logs to identify potential unauthorized access attempts. It triggers when a single source IP initiates a high volume of failed SSH login attempts (brute force) or when a single user account is targeted by multiple distinct source IPs within a short time window (password spraying).
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Ankit Mehta@Secvyn
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Detections.ai Community
27 days ago
607
Detects a sequence of authentication activity indicative of a credential stuffing attack. The rule identifies a burst of failed password-only authentication attempts followed by a successful authentication for the same account. It requires that the IP address used for the successful login overlaps with the set of IPs that initiated the failed attempts, effectively filtering out typical user noise and highlighting potentially malicious activity where an attacker has identified a valid credential.
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Arnold Chan@slaz
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Detection & Hunting Community
27 days ago
107
Detects anomalous authentication patterns where a single source IP targets a high number of unique user accounts with failed authentication attempts over a rolling window. By filtering out SSO/Federated methods and specific service account patterns, this rule isolates low-and-slow brute-force or password-spraying activities designed to evade standard account lockout mechanisms.
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Ankit Mehta@Secvyn
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Detections.ai Community
27 days ago
006
Detects anomalous AWS activity combining bulk secret retrieval from AWS Secrets Manager using the BatchGetSecretValue API with subsequent authentication failures or validation errors in AWS STS. This behavior is indicative of automated credential harvesting pipelines or agentic frameworks rapidly enumerating and testing stolen credentials.
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Ibrahim Saud@tektrix
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Detections.ai Community
1 month ago
0032
This rule detects a password-spraying attack pattern directed at privileged or manager-titled accounts. It monitors for multiple failed sign-in attempts from a single source IP address against a large volume of distinct user accounts identified as managers or senior staff. The detection logic filters for low-frequency attempts per account, which is indicative of a distributed spray attack designed to evade account lockout thresholds while focusing on high-value targets.
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Arnold Chan@slaz
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Detection & Hunting Community
1 month ago
1013
Detects credential stuffing in Entra ID sign-in logs: one source IP failing against many distinct accounts within an hour, then succeeding on a small number of them.
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Arnold Chan@slaz
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Hunters
19 days ago
000
Detects a sequence of authentication activity indicative of a credential stuffing attack. The rule identifies a burst of failed password-only authentication attempts followed by a successful authentication for the same account. It requires that the IP address used for the successful login overlaps with the set of IPs that initiated the failed attempts, effectively filtering out typical user noise and highlighting potentially malicious activity where an attacker has identified a valid credential.
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Arnold Chan@slaz
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Hunters
27 days ago
105
Detects a sequence of authentication activity indicative of a credential stuffing attack. The rule identifies a burst of failed password-only authentication attempts followed by a successful authentication for the same account. It requires that the IP address used for the successful login overlaps with the set of IPs that initiated the failed attempts, effectively filtering out typical user noise and highlighting potentially malicious activity where an attacker has identified a valid credential.
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Arnold Chan@slaz
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Detections.ai Community
27 days ago
005
This rule detects potential brute-force activity against remote access services (OpenVPN, StrongSwan, WireGuard, and SSH) on Linux hosts by monitoring Syslog for patterns indicating repeated failed authentication attempts. It further highlights instances where a burst of failed attempts is followed by a successful authentication for the same source IP, indicating a potential successful compromise.
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Ankit Mehta@Secvyn
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Detections.ai Community
27 days ago
204
Detects repeated SSH authentication failures originating from an external source on port 22, where the username pattern appears to be programmatically generated or enumerated (e.g., username followed by digits). This behavior is characteristic of automated brute-force attempts targeting common SSH services.
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Ankit Mehta@Secvyn
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Detections.ai Community
27 days ago
004
Detects a sequence of authentication activity indicative of a credential stuffing attack. The rule identifies a burst of failed password-only authentication attempts followed by a successful authentication for the same account. It requires that the IP address used for the successful login overlaps with the set of IPs that initiated the failed attempts, effectively filtering out typical user noise and highlighting potentially malicious activity where an attacker has identified a valid credential.
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Arnold Chan@slaz
Defender - KQL
27 days ago
004
Detects Microsoft Entra ID (formerly Azure AD) sign-in attempts that use the specific, hardcoded User-Agent string associated with the TeamFiltration tool. This tool is frequently used for mass credential testing against Microsoft 365 environments. The detection looks for a suspicious and outdated combination of Teams, Electron, and Chrome versions that would not be present in legitimate, modern Microsoft Teams client traffic.
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Ankit Mehta@Secvyn
Bharat Cyber Guardians
27 days ago
004
Detects potential MFA push fatigue (bombing) attacks by identifying users who receive an abnormal frequency of MFA push notification denials or interruptions within a short window, followed immediately by a successful authentication on a previously unseen device fingerprint. This pattern is characteristic of attackers attempting to wear down users into approving unauthorized login requests.
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Ibrahim Saud@tektrix
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Detections.ai Community
28 days ago
104
This rule detects a potential brute force attack against the Microsoft SQL Server 'sa' administrative account. It identifies a high volume of failed authentication events (Event ID 18456) for the 'sa' account within a 10-minute window, followed by a successful authentication event (Event ID 18453 or 18454) from the same source IP address. The rule specifically filters for successful logins originating from non-private (internet-facing) IP addresses, suggesting an attempt from an external threat actor.
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Ibrahim Saud@tektrix
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Detections.ai Community
29 days ago
005
This rule identifies potential brute force or password spraying attacks against network edge devices, such as firewalls and VPN gateways. It aggregates authentication failures and denied connection attempts by source IP address. The rule differentiates between brute force attacks, characterized by a high volume of failed attempts against one or more users from a single source, and password spraying, indicated by multiple unique usernames failing authentication from the same source.
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Ankit Mehta@Secvyn
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Detections.ai Community
27 days ago
003
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