PH_Rule_SIGMA_535
Enabled
Detects suspicious command lines used in Covenant luanchers. This rule is adapted from https://github.com/SigmaHQ/sigma/blob/master/rules/windows/process_creation/proc_creation_win_hktl_covenant.yml
7
Security
Defense Evasion
Defense Evasion consists of techniques that adversaries use to avoid detection throughout their compromise. Techniques used for defense evasion include uninstalling/disabling security software or obfuscating/encrypting data and scripts. Adversaries also leverage and abuse trusted processes to hide and masquerade their malware. Other tactics’ techniques are cross-listed here when those techniques include the added benefit of subverting defenses.
https://attack.mitre.org/tactics/TA0005T1564.003
Hide Artifacts: Hidden Window
Adversaries may use hidden windows to conceal malicious activity from the plain sight of users. In some cases, windows that would typically be displayed when an application carries out an operation can be hidden. This may be utilized by system administrators to avoid disrupting user work environments when carrying out administrative tasks. Adversaries may abuse these functionalities to hide otherwise visible windows from users so as not to alert the user to adversary activity on the system.
https://attack.mitre.org/techniques/T1564/003Server
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 ((command REGEXP ".*-Sta.*" AND command REGEXP ".*-Nop.*" AND command REGEXP ".*-Window.*" AND command REGEXP ".*Hidden.*" AND command REGEXP ".*-Command.*|.*-EncodedCommand.*") OR command REGEXP ".*-EncodedCommand cwB2ACAAbwAgA.*|.*GruntHTTP.*|.*mshta file\.hta.*|.*sv o \(New-Object IO\.MemorySteam\);sv d .*")
This defines how matching events are aggregated, only events with the same matching attribute values are grouped into one unique incident ID
command,hostName
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
command = Filter.command,
hostName = Filter.hostName