Detection rules › Sigma

Potential Regsvr32 Commandline Flag Anomaly

Severity
medium
Author
Florian Roth (Nextron Systems)
Source
upstream

Detects a potential command line flag anomaly related to "regsvr32" in which the "/i" flag is used without the "/n" which should be uncommon.

MITRE ATT&CK coverage

TacticTechniques
Defense EvasionT1218.010 System Binary Proxy Execution: Regsvr32

Event coverage

ProviderEvent IDTitle
Sysmon1Process creation
Security-Auditing4688A new process has been created.

Stages and Predicates

Stage 1: selection

CommandLine|contains: ' -i:'
Image|endswith: '\regsvr32.exe'

Stage 2: not 1 of filter_main_flag

CommandLine|contains: ' -n '

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

FieldKindValues
CommandLinematch
  • -i:
  • -n corpus 5 (sigma 5)
Imageends_with
  • \regsvr32.exe corpus 57 (sigma 57)