Detections

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

1,235 detections

Detects the addition of users to specific high-value or sensitive groups in Microsoft Entra ID (Azure AD), which could indicate potential unauthorized privilege escalation or persistence attempts by an attacker.
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Ankit Mehta@Secvyn
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Detections.ai Community
4 months ago
305
This rule detects authentication events for service accounts (matching patterns like 'svc', 'sa', 'service') originating from at least two different countries within a short time window (30 minutes or less), indicating potential credential compromise and anomalous geographic movement.
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Ankit Mehta@Secvyn
Bharat Cyber Guardians
4 months ago
304
Threat hunting query designed to identify suspicious FortiGate SSL-VPN and administrative authentication activity that may indicate credential abuse following the FortiBleed 2026 credential exposure campaign.

This hunt focuses on post-exposure behavior rather than vulnerability exploitation and combines multiple hunting hypotheses, including:

- Previously unseen user/IP combinations
- Multiple users authenticating from the same source IP
- Single users authenticating from multiple source IPs
- Rapid country changes resembling impossible-travel scenarios
- Administrative account creation or modification
- Firewall and VPN configuration changes
- Potential tunneling or proxy activity associated with post-compromise operations

The objective is to identify unauthorized access resulting from exposed FortiGate administrator credentials or SSL-VPN credentials.

This query is intended as a hunting starting point and should be adapted to local FortiGate log formats, parser mappings, enrichment sources and operational requirements.
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Michael Fajkus@MilesDyson
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Detections.ai Community
4 months ago
273141
This rule monitors for successful and failed user authentication events (Logon events 4624 and 4625) occurring on Saturdays or Sundays. It calculates a risk score based on the volume of authentication attempts and classifies the activity, providing visibility into potential off-hours credential misuse or insider threat scenarios.
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Ankit Mehta@Secvyn
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Detections.ai Community
4 months ago
004
Detects signs of the VerdantBamboo threat actor's BRICKSTORM/PLENET campaign, specifically targeting Linux-based edge appliances like pfSense and Synology NAS. The rule monitors for sudo abuse by specific service accounts (e.g., egnyteservice, www-data) attempting to leverage NOPASSWD sudo privileges for the 'tee' utility to write malicious content into sensitive system files (e.g., /usr/sbin/, /etc/cron.d/, /etc/sudoers). Additionally, it identifies unauthorized sudo enumeration commands that may indicate early-stage reconnaissance or persistence efforts.
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Ibrahim Saud@tektrix
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Detections.ai Community
4 months ago
003
Detects successful Microsoft 365 user authentications where Conditional Access (CA) policies were bypassed, resulting in single-factor authentication. This pattern is indicative of attackers using compromised edge network appliances—which are often configured as trusted network locations—to proxy authentication requests and circumvent security controls.
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Ibrahim Saud@tektrix
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Detections.ai Community
4 months ago
003
Detects SSH, SFTP, or SCP connections originating from internal edge appliances such as pfSense firewalls or Synology NAS devices directed at internal network hosts. This activity is consistent with VerdantBamboo BRICKSTORM lateral movement, where compromised edge infrastructure is leveraged as a pivot point to gain access to the internal network.
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Ibrahim Saud@tektrix
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Detections.ai Community
4 months ago
103
Detects a sequence of events within a 30-minute window for a single user, specifically capturing MFA configuration changes (reset/enrollment), authentication, and device registration, occurring outside of typical business hours (20:00 - 06:00). This behavioral pattern is often indicative of an adversary establishing persistence or account takeover after gaining access to a valid account.
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Ankit Mehta@Secvyn
Bharat Cyber Guardians
4 months ago
103
This rule detects multiple successful RDP logons (LogonType 10) within a one-hour window by accounts containing '$' (often machine accounts) or 'admin' (privileged accounts). This behavior can be indicative of an adversary attempting to gain remote access and potentially deploy ransomware or other malicious payloads, especially if multiple source IPs are observed.
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Ankit Mehta@Secvyn
Bharat Cyber Guardians
4 months ago
003
Detects an internet-facing host in the DMZ that receives an inbound connection from an external non-RFC1918 address and subsequently authenticates to an internal RFC1918 host within a one-hour window. This behavior is indicative of a compromised DMZ host being used as a pivot point for lateral movement into the internal network.
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Ibrahim Saud@tektrix
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Detections.ai Community
4 months ago
103
Detects instances where a guest user or an external account (identified by the #EXT# suffix) performs an operation to add a new member to a Microsoft 365 Group. This behavior can be indicative of a guest account being compromised or misused to escalate privileges or gain unauthorized access by modifying group memberships.
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Ankit Mehta@Secvyn
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Detections.ai Community
4 months ago
303
This rule identifies endpoints identified as EMS or FortiClient that exhibit an unusually high number of login events (greater than 20) or a high number of unique accounts logging in (greater than 10) within a specific timeframe. This behavior may indicate unauthorized access attempts, automated password spraying, or potential lateral movement activity directed at remote access infrastructure.
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Ibrahim Saud@tektrix
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Detections.ai Community
4 months ago
001
This rule detects successful self-service password reset (SSPR) operations performed by users from IP addresses geolocated to a country that does not match their typical sign-in activity over the past 30 days. This behavior may indicate account takeover where an adversary has compromised credentials and is resetting the password to maintain access or gain further persistence.
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Ankit Mehta@Secvyn
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Detections.ai Community
4 months ago
104
User Added to an Administrator's Azure AD Role
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SigmaHQ Detections@sigmaHQ
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SigmaHQ
4 months ago
001
Search Common EventCodes (EventID’s) for Suspicious Behavior
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Kaushal Patel@kaushal19
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Detections.ai Community
4 months ago
119
Detects attempts to clone or snapshot sensitive virtual machines (such as Domain Controllers, PKI, Vault, ADFS, or SSO servers) in a VMware environment. The rule alerts on these activities when performed by non-administrator accounts outside of established maintenance windows, suggesting potential unauthorized data staging or credential extraction.
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Ankit Mehta@Secvyn
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Detections.ai Community
4 months ago
209
Detects the execution of remote commands on cloud virtual machines (Azure RunCommand or AWS SSM SendCommand) during defined off-hours (18:00 to 06:00). This rule identifies potentially unauthorized administrative or management activity occurring outside of standard business hours across cloud environments.
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Ankit Mehta@Secvyn
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Detections.ai Community
4 months ago
108
Detects successful ROPC (Resource Owner Password Credential) token acquisitions targeting Microsoft Graph (00000003-0000-0000-c000-000000000000) where Conditional Access was not applied and only single-factor authentication was satisfied. This pattern indicates abuse of hidden CA policy scope exclusions introduced by CVE-2025-0309, enabling token issuance without MFA or device compliance enforcement.
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Ethan Andrews@eandrews
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Federal Signal Detections
4 months ago
2013
Detects high-risk activity where a user session, characterized by specific suspicious browser user agents and non-interactive authentication (indicative of token replay/session hijacking), is followed by changes to Workday payroll information (direct deposit, banking details) or unauthorized access to HR-related email content.
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Ibrahim Saud@tektrix
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Detections.ai Community
4 months ago
003
This rule detects interactive logons (LogonType 10) where a single account from the same domain logs into multiple distinct devices. This could indicate an attacker using compromised credentials to move laterally within the network or access multiple systems.
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Ankit Mehta@Secvyn
Bharat Cyber Guardians
4 months ago
103
Detects instances where a guest user or an external account (identified by the #EXT# suffix) performs an operation to add a new member to a Microsoft 365 Group. This behavior can be indicative of a guest account being compromised or misused to escalate privileges or gain unauthorized access by modifying group memberships.
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Ankit Mehta@Secvyn
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Detections.ai Community
4 months ago
303
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