PH_Rule_Change_3H
Enabled
Detects users added to backup operator group
6
Change
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/TA0003T1136.001
Create Account: Local Account
Adversaries may create a local account to maintain access to victim systems. Local accounts are those configured by an organization for use by users, remote support, services, or for administration on a single system or service. With a sufficient level of access, the net user /add
command can be used to create a local account. Such accounts may be used to establish secondary credentialed access that do not require persistent remote access tools to be deployed on the system.
Application
Windows Security Log via OMI or FortiSIEM Agent
Correlation
Make sure it is an authorized change
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.
DCUserGrpChange
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
reptDevIpAddr IN (Group@PH_SYS_DEVICE_WINDOWS_SERVER) AND eventType IN (Group@PH_SYS_EVENT_GroupMemberAdded) AND targetUserGrp = "Backup Operators"
This defines how matching events are aggregated, only events with the same matching attribute values are grouped into one unique incident ID
reptDevName, user,computer,domain,targetUser,targetUserGrp,targetDomain
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
hostName = DCUserGrpChange.reptDevName,
user = DCUserGrpChange.user,
computer = DCUserGrpChange.computer,
domain = DCUserGrpChange.domain,
targetUser = DCUserGrpChange.targetUser,
targetDomain = DCUserGrpChange.targetDomain,
targetUserGrp = DCUserGrpChange.targetUserGrp