Detections
Explore public detection logic contributed by the community across SIEM and rule languages.
827 detections
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This query shows attempts to request Kerberos service ticket using the AS service, to monitor Kerberos AS authentications.
// Detect Active Directory service accounts that are not active because their last logon was more than 14 days ago
// Replace XXX on line 4 with the naming convention start of your Active Directory service accounts
// Replace XXX on line 4 with the naming convention start of your Active Directory service accounts
'Query finds accounts recorded as disabled by AD in previous time period but still using proxy in current time period. Presumes default squid log format is used. http://www.squid-cache.org/Doc/config/access_log/'
Find accounts that have been added/removed from groups in AD.
The following query detects possible CVE-2021-42278 exploitation by finding changes of device names in the network using Microsoft Defender for Identity
This analytic detects suspicious modifications to Unix shell configuration files, such as `.bashrc` or `.profile`, which may indicate an attempt to alter system behavior or gain unauthorized access. Unauthorized changes to these files can be used to execute malicious commands, escalate privileges, or hide malicious activities. By monitoring for unusual or unauthorized modifications to shell configuration files, this analytic helps identify potential security threats, allowing security teams to respond quickly and mitigate risks.
'This detection uses Security events from the "AD FS Auditing" provider to detect suspicious object identifiers (OIDs) as part EventID 501 and specifically part of the Enhanced Key Usage attributes.
This query checks to see if you have any new OIDs in the last hour that have not been seen in the previous day. New OIDs should be validated and OIDs that are very long, as indicated
by the OID_Length field, could also be an indicator of malicious activity.
In order to use this query you need to enable AD FS auditing on the AD FS Server.
References:
https://www.microsoft.com/security/blog/2022/08/24/magicweb-nobeliums-post-compromise-trick-to-authenticate-as-anyone/
https://docs.microsoft.com/windows-server/identity/ad-fs/troubleshooting/ad-fs-tshoot-logging
'
This query checks to see if you have any new OIDs in the last hour that have not been seen in the previous day. New OIDs should be validated and OIDs that are very long, as indicated
by the OID_Length field, could also be an indicator of malicious activity.
In order to use this query you need to enable AD FS auditing on the AD FS Server.
References:
https://www.microsoft.com/security/blog/2022/08/24/magicweb-nobeliums-post-compromise-trick-to-authenticate-as-anyone/
https://docs.microsoft.com/windows-server/identity/ad-fs/troubleshooting/ad-fs-tshoot-logging
'
The following analytic detects attempts to stop a service on Linux systems. It leverages data from Linux Auditd. This activity is significant as adversaries often stop or terminate security or critical services to disable defenses or disrupt operations, as seen in malware like Industroyer2. If confirmed malicious, this could lead to the disabling of security mechanisms, allowing attackers to persist, escalate privileges, or deploy destructive payloads, severely impacting system integrity and availability.
The following analytic detects the suspicious auditd service stop. This behavior is critical for a SOC to monitor because it may indicate attempts to gain unauthorized access or maintain control over a system. Such actions could be signs of malicious activity. If confirmed, this could lead to serious consequences, including a compromised system, unauthorized access to sensitive data, or even a wider breach affecting the entire network. Detecting and responding to these signs early is essential to prevent potential security incidents.
The analytic detects cloud API calls executed by user roles that have not previously run these commands. It leverages the Change data model in Splunk to identify commands executed by users with the user_type of AssumedRole and a status of success. This activity is significant because new commands from different user roles can indicate potential malicious activity or unauthorized actions. If confirmed malicious, this behavior could lead to unauthorized access, data breaches, or other damaging outcomes by exploiting new or unmonitored commands within the cloud environment.
The analytic detects the creation of cloud compute instances using previously unseen image IDs. It leverages cloud infrastructure logs to identify new image IDs that have not been observed before. This activity is significant because it may indicate unauthorized or suspicious activity, such as the deployment of malicious payloads or unauthorized access to sensitive information. If confirmed malicious, this could lead to data breaches, unauthorized access, or further compromise of the cloud environment. Immediate investigation is required to determine the legitimacy of the instance creation and to mitigate potential threats.
Detects when users are added to privileged Active Directory groups. This is a critical event as it can lead to privilege escalation and unauthorized access to sensitive resources within an Active Directory environment. The rule specifically looks for Windows Event Code 4728, which indicates a member was added to a security-enabled global group, security-enabled local group, or security-enabled universal group.
This rule detects user logins from multiple distinct states or countries within a one-hour window, leveraging GeoIP enrichment. It specifically looks for successful login events where a user logs in from at least two different states or at least one country, indicating potential 'impossible travel' or suspicious access patterns.
This rule detects attempts to access the Active Directory contact object to read the AD FS Distributed Key Manager (DKM) master key value. This activity is identified by monitoring Windows Security Event ID 4662 (An operation was performed on an object) for specific property GUIDs associated with the DKM master key, combined with a successful user login event (Event ID 4624) from the same host within a 5-minute window. This indicates a potential attempt to compromise AD FS for credential theft or persistence.
Detects uncommon network connections to the Active Directory Web Services (ADWS) on port 9389 from processes not typically associated with ADWS management. This can indicate an adversary performing discovery of Active Directory information.
Detects the creation or modification of a Windows domain group named "ESX Admins". This activity is suspicious because VMware ESXi hypervisors joined to an Active Directory domain grant full administrative access by default to members of a group with this specific name. This could indicate a potential exploitation attempt of CVE-2024-37085, which allows an attacker to elevate privileges on a domain-joined ESXi hypervisor.
This rule detects the creation of a domain group named "ESX Admins" using either `net.exe` or PowerShell cmdlets like `New-ADGroup`. This activity is highly suspicious and indicates a potential exploitation attempt of CVE-2024-37085. This vulnerability allows an attacker to elevate privileges to full administrative access on a domain-joined ESXi hypervisor, as VMware ESXi hypervisors grant full administrative access by default to members of a domain group named "ESX Admins".
Allowed Logins from Terminated Employees
Detect Multiple Failed Login Attempts followed by Successful Login
Detects denied certificate enrollment requests by Active Directory Certificate Services. This can occur due to issues such as incorrect permissions on the certificate template or invalid signatures. While the rule itself doesn't directly detect the installation of a root certificate (T1553.004), a denied request could be an indicator of an adversary attempting to enroll a certificate for malicious purposes, potentially as a precursor to establishing trust for adversary-controlled infrastructure or for code signing. The denial of such a request could be a valuable alert for suspicious activity related to certificate services.
This rule detects potential DCShadow attacks by looking for the creation of new Service Principal Names (SPNs) that contain 'GC/' in either Event ID 4742 (A computer account was changed) or Event ID 5136 (A directory service object was modified). DCShadow is a technique used by adversaries to register a rogue Domain Controller and manipulate Active Directory data.
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