New Root or CA or AuthRoot Certificate to Store

Hunt Hypothesis

Detects the addition of new root, CA or AuthRoot certificates to the Windows registry

Detection Rule

Sigma (Original)

title: New Root or CA or AuthRoot Certificate to Store
id: d223b46b-5621-4037-88fe-fda32eead684
status: test
description: Detects the addition of new root, CA or AuthRoot certificates to the Windows registry
references:
    - https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1553.004/T1553.004.md#atomic-test-6---add-root-certificate-to-currentuser-certificate-store
    - https://posts.specterops.io/code-signing-certificate-cloning-attacks-and-defenses-6f98657fc6ec
author: frack113
date: 2022-04-04
modified: 2023-08-17
tags:
    - attack.impact
    - attack.t1490
logsource:
    category: registry_set
    product: windows
detection:
    selection:
        TargetObject|contains:
            - '\SOFTWARE\Microsoft\SystemCertificates\Root\Certificates\'
            - '\SOFTWARE\Policies\Microsoft\SystemCertificates\Root\Certificates\'
            - '\SOFTWARE\Microsoft\EnterpriseCertificates\Root\Certificates\'
            - '\SOFTWARE\Microsoft\SystemCertificates\CA\Certificates\'
            - '\SOFTWARE\Policies\Microsoft\SystemCertificates\CA\Certificates\'
            - '\SOFTWARE\Microsoft\EnterpriseCertificates\CA\Certificates\'
            - '\SOFTWARE\Microsoft\SystemCertificates\AuthRoot\Certificates\'
            - '\SOFTWARE\Policies\Microsoft\SystemCertificates\AuthRoot\Certificates\'
            - '\SOFTWARE\Microsoft\EnterpriseCertificates\AuthRoot\Certificates\'
        TargetObject|endswith: '\Blob'
        Details: 'Binary Data'
    condition: selection
falsepositives:
    - Unknown
level: medium

KQL (Azure Sentinel)

imRegistry
| where (RegistryKey endswith "\\SOFTWARE\\Microsoft\\SystemCertificates\\Root\\Certificates*" or RegistryKey endswith "\\SOFTWARE\\Policies\\Microsoft\\SystemCertificates\\Root\\Certificates*" or RegistryKey endswith "\\SOFTWARE\\Microsoft\\EnterpriseCertificates\\Root\\Certificates*" or RegistryKey endswith "\\SOFTWARE\\Microsoft\\SystemCertificates\\CA\\Certificates*" or RegistryKey endswith "\\SOFTWARE\\Policies\\Microsoft\\SystemCertificates\\CA\\Certificates*" or RegistryKey endswith "\\SOFTWARE\\Microsoft\\EnterpriseCertificates\\CA\\Certificates*" or RegistryKey endswith "\\SOFTWARE\\Microsoft\\SystemCertificates\\AuthRoot\\Certificates*" or RegistryKey endswith "\\SOFTWARE\\Policies\\Microsoft\\SystemCertificates\\AuthRoot\\Certificates*" or RegistryKey endswith "\\SOFTWARE\\Microsoft\\EnterpriseCertificates\\AuthRoot\\Certificates*") and RegistryKey endswith "\\Blob" and RegistryValueData =~ "Binary Data"

KQL (Microsoft 365 Defender)

DeviceRegistryEvents
| where (RegistryKey endswith "\\SOFTWARE\\Microsoft\\SystemCertificates\\Root\\Certificates*" or RegistryKey endswith "\\SOFTWARE\\Policies\\Microsoft\\SystemCertificates\\Root\\Certificates*" or RegistryKey endswith "\\SOFTWARE\\Microsoft\\EnterpriseCertificates\\Root\\Certificates*" or RegistryKey endswith "\\SOFTWARE\\Microsoft\\SystemCertificates\\CA\\Certificates*" or RegistryKey endswith "\\SOFTWARE\\Policies\\Microsoft\\SystemCertificates\\CA\\Certificates*" or RegistryKey endswith "\\SOFTWARE\\Microsoft\\EnterpriseCertificates\\CA\\Certificates*" or RegistryKey endswith "\\SOFTWARE\\Microsoft\\SystemCertificates\\AuthRoot\\Certificates*" or RegistryKey endswith "\\SOFTWARE\\Policies\\Microsoft\\SystemCertificates\\AuthRoot\\Certificates*" or RegistryKey endswith "\\SOFTWARE\\Microsoft\\EnterpriseCertificates\\AuthRoot\\Certificates*") and RegistryKey endswith "\\Blob" and RegistryValueData =~ "Binary Data"

Required Data Sources

False Positive Guidance

• Unknown

MITRE ATT&CK Context

• Tactic: Impact
• Technique: T1490 — T1490

References

• https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1553.004/T1553.004.md#atomic-test-6---add-root-certificate-to-currentuser-certificate-store
• https://posts.specterops.io/code-signing-certificate-cloning-attacks-and-defenses-6f98657fc6ec
• SigmaHQ Rule