Detections

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

1,235 detections

Detects NTLM successful network logons where the source and destination workstations are the same, excluding loopback addresses. This behavior can be indicative of NTLM relay attacks where an attacker relays authentication from a victim to the victim's own machine, or other forms of NTLM abuse.
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R W@shiftyroot
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Detections.ai Community
1 year ago
53112
The analytic detects an unusually high number of denied Multi-Factor Authentication (MFA) requests for a single user within a 10-minute window, specifically when more than nine MFA prompts are declined. It leverages Azure Active Directory (Azure AD) sign-in logs, focusing on "Sign-in activity" events with error code 500121 and additional details indicating "MFA denied; user declined the authentication." This behavior is significant as it may indicate a targeted attack or account compromise attempt, with the user actively declining unauthorized access. If confirmed malicious, it could lead to data exfiltration, lateral movement, or further malicious activities.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
1048
Detects the reconfiguration of a virtual machine where a virtual disk (.vmdk) from a different, often critical, VM is attached. This is a key tactic used by threat actors like UNC3944 to perform offline credential theft by mounting a Domain Controller's disk to a staging VM to access the NTDS.dit file.
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Kaung Khant Ko@kaungkhantko
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Detections.ai Community
1 year ago
52131
The following analytic detects instances where a Duo admin login originates from a country outside of the United States, which may indicate suspicious or unauthorized access attempts. It works by analyzing Duo activity logs for admin login actions and filtering out events where the access device's country is not within the expected region. By correlating user, device, browser, and location details, the analytic highlights anomalies in geographic login patterns. This behavior is critical for a SOC to identify because admin accounts have elevated privileges, and access from unusual countries can be a strong indicator of credential compromise, account takeover, or targeted attacks. Early detection of such activity enables rapid investigation and response, reducing the risk of unauthorized changes, data breaches, or further lateral movement within the environment. The impact of this attack can be severe, potentially allowing attackers to bypass security controls, alter configurations, or exfiltrate sensitive information.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
100111
Detects potential exploitation of Microsoft Entra ID (formerly Azure AD) by attackers who abuse app role permissions to backdoor federated domains and escalate to Global Administrator using forged SAML tokens
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Chaitanya B B@mralien
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Detections.ai Community
1 year ago
125109
The analytic identifies instances where a Duo admin logs in using a browser other than Chrome, which is considered unusual based on typical access patterns. This behavior is significant for a SOC because the use of an unexpected browser may indicate credential compromise, session hijacking, or the use of unauthorized devices by attackers attempting to evade detection. Detecting such anomalies enables early investigation and response, helping to prevent privilege escalation, policy manipulation, or further compromise of sensitive administrative accounts. The impact of this attack could include unauthorized changes to security policies, user access, or the disabling of critical security controls, posing a substantial risk to the organizations security posture.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
3053
Threat hunting query looking for successful logon events with user agent strings that are uncommon within your environment.
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frog 🐸@frog
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Detections.ai Community
1 year ago
4572
This detection identifies the creation, deletion, or modification of a local user account on an ESXi host. This activity may indicate unauthorized access, indicator removal, or persistence attempts by an attacker seeking to establish or maintain control of the host.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
1089
This detection identifies instances where the ESXi UI is accessed using the root account from an external IP address. Direct root access to the UI bypasses role-based access controls and auditing practices, and may indicate risky behavior, misconfiguration, or unauthorized activity by a malicious actor using compromised credentials.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
1056
This detection monitors for signs of a shared or potentially compromised root account on ESXi hosts by tracking the number of unique IP addresses logging in as root within a short time window. Multiple logins from different IPs in a brief period may indicate credential misuse, lateral movement, or account compromise.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
1046
This detection identifies when a user is granted the Administrator role on an ESXi host. Assigning elevated privileges is a critical action that can indicate potential malicious behavior if performed unexpectedly. Adversaries who gain access may use this to escalate privileges, maintain persistence, or disable security controls.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
1045
This rule detects potentially malicious sign-in attempts that occur shortly after a user clicks on a URL, especially when the sign-in originates from a different IP address or subnet than the URL click. It specifically looks for risky sign-ins to Microsoft first-party applications. The logic aims to identify scenarios where a user might be phished (e.g., via a malicious link) and then their credentials are used to sign in from an attacker-controlled location.
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Phong Huynh@phong
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Detections.ai Community
1 year ago
205229
KQL Query from file: Threat Hunt: Potential Password Spray Attacks
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Awais Munir@iawais
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Detections.ai Community
1 year ago
161183
KQL Query from file: Potential MFASweep (tool) activity has been detected.
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Boaz B@82BBB00
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Detections.ai Community
1 year ago
94135
Detects when a Global Administrator elevates access to all subscriptions and management groups in a tenant. When a Global Administrator elevates access they are assigned the User Access Administrator role at root scope. This Sentinel analytics rule monitors who has elevated access in your tenant so that admins can take appropriate action.
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Andre Zeemering@Azeemering
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Detections.ai Community
1 year ago
84113
Generic rule content from file: Initial Access - Probable Rogue ScreenConnect Session
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Marcus Mingo@meeengoh
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Tr&de
1 year ago
9183
KQL Query from file: GraphRunner Recon Detection & Response
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Steven Lim@KQLWizard
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SlimKQL
1 year ago
61354
KQL Query from file: Threat Hunting AzureHound Usage
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Steven Lim@KQLWizard
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SlimKQL
1 year ago
101272
KQL Query from file: Detect Microsoft Graph API Abuse
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Steven Lim@KQLWizard
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SlimKQL
1 year ago
130173
KQL Query from file: Monitor Privilege User SSPR
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Steven Lim@KQLWizard
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SlimKQL
1 year ago
91172
Search Common EventCodes (EventID’s) for Suspicious Behavior
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Kaushal Patel@kaushal19
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Detections.ai Community
1 year ago
2150
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