Detect Subvert Trust Controls in Google Chronicle
Adversaries may undermine security controls that warn users of untrusted activity or prevent execution of untrusted programs. Operating systems and security products contain mechanisms to identify programs or websites as possessing some level of trust, such as code signing certificates, Mark-of-the-Web (MOTW) attributes, Gatekeeper on macOS, or SIP and Trust Provider validation on Windows. Adversaries attempt to subvert these trust mechanisms through techniques including code signing certificate theft or forgery, MOTW removal, root certificate installation, SIP/Trust Provider hijacking, and Gatekeeper bypass. The method used depends on the specific mechanism being subverted.
MITRE ATT&CK
- Tactic
- Defense Evasion
- Technique
- T1553 Subvert Trust Controls
- Canonical reference
- https://attack.mitre.org/techniques/T1553/
YARA-L Detection Query
rule t1553_subvert_trust_controls {
meta:
author = "Detection Engineering"
description = "Detects T1553 Subvert Trust Controls: certutil certificate store manipulation, MOTW removal via Zone.Identifier or Unblock-File, signtool signing, certificate creation tools, and trust provider registry modifications"
mitre_attack_tactic = "Defense Evasion"
mitre_attack_technique = "T1553"
reference = "https://attack.mitre.org/techniques/T1553/"
severity = "HIGH"
priority = "HIGH"
events:
(
$e.metadata.event_type = "PROCESS_LAUNCH" and
(
(
re.regex($e.target.process.file.full_path, `(?i)certutil\.exe$`) and
re.regex($e.target.process.command_line, `(?i)(-addstore|-delstore|-importpfx|-enterprise)`)
) or
(
re.regex($e.target.process.file.full_path, `(?i)(powershell|pwsh|cmd)\.exe$`) and
re.regex($e.target.process.command_line, `(?i)(unblock-file|zone\.identifier|zoneid)`)
) or
(
re.regex($e.target.process.file.full_path, `(?i)signtool\.exe$`) and
re.regex($e.target.process.command_line, `(?i)\bsign\b`)
) or
re.regex($e.target.process.file.full_path, `(?i)(makecert|pvk2pfx)\.exe$`)
)
) or
(
$e.metadata.event_type = "REGISTRY_MODIFICATION" and
re.regex($e.target.registry.registry_key,
`(?i)(SOFTWARE.Microsoft.Cryptography.(OID|Providers)|SOFTWARE.(Policies.Microsoft.SystemCertificates|Microsoft.EnterpriseCertificates)|SYSTEM.CurrentControlSet.Control.SecurityProviders)`
)
)
condition:
$e
}Chronicle YARA-L 2.0 rule detecting T1553 Subvert Trust Controls. Matches PROCESS_LAUNCH events for certutil store manipulation, PowerShell/cmd MOTW removal, signtool signing, and certificate creation tools (makecert, pvk2pfx). Also matches REGISTRY_MODIFICATION events targeting Windows cryptography OID, provider, enterprise certificate, and security provider registry paths. Designed for UDM telemetry ingested via Chronicle forwarder from Sysmon, Windows Defender ATP, or CrowdStrike Falcon.
Data Sources
Required Tables
False Positives & Tuning
- Enterprise PKI operations using certutil to distribute root CA certificates across managed fleets during certificate renewal cycles will match the certutil branch extensively across all enrolled endpoints simultaneously
- Software development teams with integrated code signing workflows will generate frequent signtool.exe detections on build servers, developer workstations, and automated CI/CD agents throughout the business day
- Windows Group Policy-enforced certificate trust updates and Windows Update processes may modify SystemCertificates and Cryptography registry paths as part of normal OS patch and policy enforcement cycles
Other platforms for T1553
Testing Methodology
Validate this detection against 4 adversary techniques from Atomic Red Team. Each test below lists the behaviour to exercise and the telemetry you should expect to see. Executable commands and cleanup steps are available with Pro.
- Test 1Add Self-Signed Root Certificate to Windows ROOT Store
Expected signal: Sysmon Event ID 1: Process Create with Image=certutil.exe, CommandLine containing '-addstore ROOT'. Security Event ID 4688 (if command line auditing enabled). Windows CertificateServicesClient-Lifecycle-System/Operational Event ID 1001 (certificate installed). CAPI2 Operational log entries for certificate store modification.
- Test 2Remove Mark-of-the-Web via PowerShell Unblock-File
Expected signal: Sysmon Event ID 1: powershell.exe with CommandLine containing 'Unblock-File' and the target file path. Sysmon Event ID 23 or 26 (File Delete) for the Zone.Identifier ADS removal. PowerShell ScriptBlock Log Event ID 4104 showing the Unblock-File command. Security Event ID 4663 (object access) if file system auditing is enabled for the temp directory.
- Test 3Remove Zone.Identifier ADS via cmd.exe del command
Expected signal: Sysmon Event ID 1: cmd.exe with CommandLine containing 'Zone.Identifier' and 'del'. Sysmon Event ID 23 (File Delete) for the ADS. Security Event ID 4688 if command line auditing is enabled. Note: some EDR solutions specifically monitor for ADS deletion on .exe files.
- Test 4Inspect and Enumerate SIP Trust Provider Registry Keys
Expected signal: Sysmon Event ID 1: reg.exe with CommandLine querying Cryptography\OID paths. Security Event ID 4663 (registry object access) if registry auditing is enabled. No modifications occur — this tests detection of enumeration prior to hijacking.
References (9)
- https://attack.mitre.org/techniques/T1553/
- https://specterops.io/assets/resources/SpecterOps_Subverting_Trust_in_Windows.pdf
- https://posts.specterops.io/code-signing-certificate-cloning-attacks-and-defenses-6f98657fc6ec
- https://securelist.com/why-you-shouldnt-completely-trust-files-signed-with-digital-certificates/68593/
- https://learn.microsoft.com/en-us/windows/win32/seccrypto/subject-interface-packages
- https://learn.microsoft.com/en-us/sysinternals/downloads/streams
- https://learn.microsoft.com/en-us/defender-endpoint/advanced-hunting-deviceregistryevents-table
- https://github.com/redcanaryco/atomic-red-team/blob/master/atomics/T1553/T1553.md
- https://github.com/SigmaHQ/sigma/tree/master/rules/windows/registry
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