PH_Rule_SIGMA_1661
Enabled
Detects suspicious processes including shells spawnd from WinRM host process. This rule is adapted from https://github.com/SigmaHQ/sigma/blob/master/rules/windows/process_creation/proc_creation_win_winrm_susp_child_process.yml
7
Security
Initial Access
Initial Access consists of techniques that use various entry vectors to gain their initial foothold within a network. Techniques used to gain a foothold include targeted spearphishing and exploiting weaknesses on public-facing web servers. Footholds gained through initial access may allow for continued access, like valid accounts and use of external remote services, or may be limited-use due to changing passwords.
https://attack.mitre.org/tactics/TA0001T1190
Exploit Public-Facing Application
Adversaries may attempt to take advantage of a weakness in an Internet-facing computer or program using software, data, or commands in order to cause unintended or unanticipated behavior. The weakness in the system can be a bug, a glitch, or a design vulnerability. These applications are often websites, but can include databases, standard services, and any other applications with Internet accessible open sockets, such as web servers and related services. Depending on the flaw being exploited this may include Exploitation for Defense Evasion.
https://attack.mitre.org/techniques/T1190Server
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 "\\wsmprovhost\.exe$" AND procName REGEXP "\\bash\.exe$|\\bitsadmin\.exe$|\\certutil\.exe$|\\cmd\.exe$|\\powershell\.exe$|\\pwsh\.exe$|\\schtasks\.exe$|\\sh\.exe$|\\whoami\.exe$|\\wsl\.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