PH_Rule_SIGMA_1511
Enabled
Detects suspicious sub processes started by the ScreenConnect client service, which indicates the use of the so-called Backstage mode. This rule is adapted from https://github.com/SigmaHQ/sigma/blob/master/rules/windows/process_creation/proc_creation_win_remote_access_tools_screenconnect_anomaly.yml
7
Security
Command And Control
T1219
Remote Access Software
An adversary may use legitimate desktop support and remote access software, such as Team Viewer, Go2Assist, LogMein, AmmyyAdmin, etc, to establish an interactive command and control channel to target systems within networks. These services are commonly used as legitimate technical support software, and may be allowed by application control within a target environment.
https://attack.mitre.org/techniques/T1219Server
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="Win-Sysmon-1-Create-Process" AND parentProcName REGEXP "ScreenConnect\.ClientService\.exe$" AND procName REGEXP "\\cmd\.exe$|\\powershell\.exe$|\\pwsh\.exe$"
This defines how matching events are aggregated, only events with the same matching attribute values are grouped into one unique incident ID
hostName,parentProcName,procName
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 = Filter.hostName,
parentProcName = Filter.parentProcName,
procName = Filter.procName