PH_Rule_SIGMA_244
Enabled
Detects Mimikatz DC sync security events. Mimikatz is a open source malware program that is commonly used by hackers and security professionals to extract sensitive information, such as passwords and credentials, from a system's memory. Mimkatz “DCSync” feature effectively “impersonates” a Domain Controller and requests account password data from the targeted Domain Controller. This rule is adapted from https://github.com/SigmaHQ/sigma/blob/master/rules/windows/builtin/security/win_security_dcsync.yml
7
Security
Credential Access
Credential Access consists of techniques for stealing credentials like account names and passwords. Techniques used to get credentials include keylogging or credential dumping. Using legitimate credentials can give adversaries access to systems, make them harder to detect, and provide the opportunity to create more accounts to help achieve their goals.
https://attack.mitre.org/tactics/TA0006T1003.006
OS Credential Dumping: DCSync
Adversaries may attempt to access credentials and other sensitive information by abusing a Windows Domain Controller's application programming interface to simulate the replication process from a remote domain controller using a technique called DCSync.
https://attack.mitre.org/techniques/T1003/006Server
Windows Security Log via OMI or FortiSIEM Agent
Correlation
Mimikatz is intended to be used by penetration testers and security red teams to simulate a real cyberthreat. Investigate whether the user needs to really run Mimikatz. Investigate what other incidents are occurring on that host during that time frame. If necessary, rebuild the host from a known, good source and have the user change their password.
If the following pattern or patterns match an ingested event within the given time window in seconds, trigger an incident.
300 seconds
If the following defined pattern/s occur within a 300 second time window.
Filter
This is the named definition of the event query, this is important if multiple subpatterns are defined to distinguish them.
This is the query logic that matches incoming events
(eventType="Win-Security-4662" AND propName REGEXP ".*1131f6aa-9c07-11d1-f79f-00c04fc2dcd2.*|.*1131f6ad-9c07-11d1-f79f-00c04fc2dcd2.*|.*89e95b76-444d-4c62-991a-0facbeda640c.*|.*9923a32a-3607-11d2-b9be-0000f87a36b2.*|.*Replicating Directory Changes All.*" AND fileAccess="0x100") AND ((domain!="Window Manager") AND (user NOT REGEXP "^MSOL_|^NT AUT") AND (user NOT REGEXP "\$$"))
This defines how matching events are aggregated, only events with the same matching attribute values are grouped into one unique incident ID
domain,fileAccess,hostName,propName,user
This is most typically a numerical constraint that defines when the rule should trigger an incident
COUNT(*) >= 1
This section defines which fields in matching raw events should be mapped to the incident attributes in the resulting incident.
The available raw event attributes to map are limited to the group by attributes and the aggregate event constraint fields for each subpattern
domain = Filter.domain,
fileAccess = Filter.fileAccess,
hostName = Filter.hostName,
propName = Filter.propName,
user = Filter.user