Detection rules › Sigma

New Root Certificate Installed Via CertMgr.EXE

Severity
medium
Author
oscd.community, @redcanary, Zach Stanford @svch0st
Source
upstream

Detects execution of "certmgr" with the "add" flag in order to install a new certificate on the system. Adversaries may install a root certificate on a compromised system to avoid warnings when connecting to adversary controlled web servers.

MITRE ATT&CK coverage

TacticTechniques
Defense EvasionT1553.004 Subvert Trust Controls: Install Root Certificate

Event coverage

ProviderEvent IDTitle
Sysmon1Process creation

Stages and Predicates

Stage 1: all of selection_img

or:
Image|endswith: '\CertMgr.exe'
OriginalFileName: CERTMGT.EXE

Stage 2: all of selection_cli

CommandLine|contains: '/add'
CommandLine|contains: root

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
  • /add corpus 3 (sigma 3)
  • root corpus 2 (sigma 2)
Imageends_with
  • \CertMgr.exe
OriginalFileNameeq
  • CERTMGT.EXE