Suspicious SYSTEM User Process Creation
A Sigma rule for process creation on Windows, by Florian Roth (Nextron Systems), David ANDRE (additional keywords).
high 3 ATT&CK techniques 9 programs it names
What it looks for
detection:
filter_config_mgr:
ParentImage|contains: ':\Packages\Plugins\Microsoft.GuestConfiguration.ConfigurationforWindows\'
filter_java:
CommandLine|contains: ' -ma '
Image|contains:
- ':\Program Files (x86)\Java\'
- ':\Program Files\Java\'
Image|endswith: '\bin\jp2launcher.exe'
ParentImage|contains:
- ':\Program Files (x86)\Java\'
- ':\Program Files\Java\'
ParentImage|endswith: '\bin\javaws.exe'
filter_main_ping:
CommandLine|contains|all:
- 'ping'
- '127.0.0.1'
- ' -n '
filter_vs:
Image|endswith: '\PING.EXE'
ParentCommandLine|contains: '\DismFoDInstall.cmd'
selection:
IntegrityLevel:
- 'System'
- 'S-1-16-16384'
User|contains:
- 'AUTHORI'
- 'AUTORI'
selection_special:
- Image|endswith:
- '\calc.exe'
- '\cscript.exe'
- '\forfiles.exe'
- '\hh.exe'
- '\mshta.exe'
- '\ping.exe'
- '\wscript.exe'
- CommandLine|re: 'net\s+user\s+'
- CommandLine|contains:
- ' -NoP '
- ' -W Hidden '
- ' -decode '
- ' /decode '
- ' /urlcache '
- ' -urlcache '
- ' -e* JAB'
- ' -e* SUVYI'
- ' -e* SQBFAFgA'
- ' -e* aWV4I'
- ' -e* IAB'
- ' -e* PAA'
- ' -e* aQBlAHgA'
- 'vssadmin delete shadows'
- 'reg SAVE HKLM'
- ' -ma '
- 'Microsoft\Windows\CurrentVersion\Run'
- '.downloadstring('
- '.downloadfile('
- ' /ticket:'
- 'dpapi::'
- 'event::clear'
- 'event::drop'
- 'id::modify'
- 'kerberos::'
- 'lsadump::'
- 'misc::'
- 'privilege::'
- 'rpc::'
- 'sekurlsa::'
- 'sid::'
- 'token::'
- 'vault::cred'
- 'vault::list'
- ' p::d '
- ';iex('
- 'MiniDump'
condition: all of selection* and not 1 of filter_*
The rule’s detection, its selections and fields in order of name. The whole rule, with its references and false positives, is on SigmaHQ, by Florian Roth (Nextron Systems), David ANDRE (additional keywords), under the Detection Rule License 1.1. CmdID evaluates it on a command line alone: a test on what a command line cannot show, such as the parent process or the user, is not met.
None of the everyday examples and documented commands on CmdID’s program pages trips it. To see whether a command line does, paste it into CmdID.