PH_Rule_SIGMA_671
Enabled
Detects a method to load DLL via LSASS process using an undocumented Registry key. This rule is adapted from https://github.com/SigmaHQ/sigma/blob/master/rules/windows/registry/registry_event/registry_event_susp_lsass_dll_load.yml
7
Security
Persistence
Persistence consists of techniques that adversaries use to keep access to systems across restarts, changed credentials, and other interruptions that could cut off their access. Techniques used for persistence include any access, action, or configuration changes that let them maintain their foothold on systems, such as replacing or hijacking legitimate code or adding startup code.
https://attack.mitre.org/tactics/TA0003T1547.008
Boot or Logon Autostart Execution: LSASS Driver
Adversaries may modify or add LSASS drivers to obtain persistence on compromised systems. The Windows security subsystem is a set of components that manage and enforce the security policy for a computer or domain. The Local Security Authority (LSA) is the main component responsible for local security policy and user authentication. Adversaries may target LSASS drivers to obtain persistence. By either replacing or adding illegitimate drivers (e.g., Hijack Execution Flow), an adversary can use LSA operations to continuously execute malicious payloads.
https://attack.mitre.org/techniques/T1547/008Server
Windows Sysmon via FortiSIEM Agent
Correlation
No remediation guidance specified
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 REGEXP "Win-Sysmon-12-Registry-.*|Win-Sysmon-13-Registry-.*|Win-Sysmon-14-Registry-.*" AND regKeyPath REGEXP ".*\\CurrentControlSet\\Services\\NTDS\\DirectoryServiceExtPt.*|.*\\CurrentControlSet\\Services\\NTDS\\LsaDbExtPt.*" AND ((procName!="C:\\Windows\\system32\\lsass.exe" OR details NOT IN ("%%systemroot%%\\system32\\lsadb.dll","%%systemroot%%\\system32\\ntdsa.dll")))
This defines how matching events are aggregated, only events with the same matching attribute values are grouped into one unique incident ID
details,hostName,procName,regKeyPath
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
details = Filter.details,
hostName = Filter.hostName,
procName = Filter.procName,
regKeyPath = Filter.regKeyPath