PH_Rule_SIGMA_360
Enabled
Detects remote PowerShell connections by monitoring network outbound connections to ports 5985 or 5986 from a non-network service account. This rule is adapted from https://github.com/SigmaHQ/sigma/blob/master/rules/windows/network_connection/net_connection_win_remote_powershell_session_network.yml
7
Security
Execution
Execution consists of techniques that result in adversary-controlled code running on a local or remote system. Techniques that run malicious code are often paired with techniques from all other tactics to achieve broader goals, like exploring a network or stealing data. For example, an adversary might use a remote access tool to run a PowerShell script that does Remote System Discovery.
https://attack.mitre.org/tactics/TA0002T1059.001
Command and Scripting Interpreter: PowerShell
Adversaries may abuse PowerShell commands and scripts for execution. Adversaries can use PowerShell to perform a number of actions, including discovery of information and execution of code.
https://attack.mitre.org/techniques/T1059/001Server
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-3-Network-Connect.*" AND (destIpPort IN (5985,5986) AND initiated="true") AND ((user NOT REGEXP ".*NETWORK SERVICE.*|.*NETZWERKDIENST.*|.*SERVICIO DE RED.*|.*SERVIZIO DI RETE.*" AND user NOT REGEXP ".*SERVICE R.*" OR user NOT REGEXP ".*SEAU.*" AND srcIpAddr NOT IN (127.0.0.1,::1) AND procName NOT IN ("C:\\Program Files (x86)\\Avast Software\\Avast\\AvastSvc.exe","C:\\Program Files\\Avast Software\\Avast\\AvastSvc.exe")) AND (srcIpAddr NOT IN (127.0.0.1,::1) OR destIpAddr NOT IN (127.0.0.1,::1)))
This defines how matching events are aggregated, only events with the same matching attribute values are grouped into one unique incident ID
destIpAddr,destIpPort,hostName,initiated,procName,srcIpAddr,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
destIpAddr = Filter.destIpAddr,
destIpPort = Filter.destIpPort,
hostName = Filter.hostName,
initiated = Filter.initiated,
procName = Filter.procName,
srcIpAddr = Filter.srcIpAddr,
user = Filter.user