Detect SIP and Trust Provider Hijacking in Elastic Security
Adversaries may tamper with Subject Interface Package (SIP) and trust provider components to mislead the operating system and application control tools during Authenticode signature validation. SIPs provide an abstraction layer between the WinVerifyTrust API and specific file formats, identified by GUIDs in the registry. Adversaries hijack these components by modifying Dll and FuncName registry values under HKLM\SOFTWARE[\WOW6432Node]\Microsoft\Cryptography\OID\EncodingType 0\CryptSIPDllGetSignedDataMsg\{GUID} (to return a forged known-good certificate) or CryptSIPDllVerifyIndirectData\{GUID} (to always return TRUE for hash validation). Trust providers may be hijacked by modifying $DLL and $Function values under HKLM\SOFTWARE\Microsoft\Cryptography\Providers\Trust\FinalPolicy\{GUID}. This allows malicious or unsigned code to appear validly signed to application whitelisting tools, AppLocker, WDAC, and SmartScreen. Because SIP components are invoked by any process performing signature validation, hijacking them also provides persistent code execution opportunities.
MITRE ATT&CK
- Tactic
- Defense Evasion
- Technique
- T1553 Subvert Trust Controls
- Sub-technique
- T1553.003 SIP and Trust Provider Hijacking
- Canonical reference
- https://attack.mitre.org/techniques/T1553/003/
Elastic Detection Query
registry where
(
registry.path : "*\\Microsoft\\Cryptography\\OID\\EncodingType 0\\CryptSIPDllGetSignedDataMsg\\*" or
registry.path : "*\\Microsoft\\Cryptography\\OID\\EncodingType 0\\CryptSIPDllVerifyIndirectData\\*" or
registry.path : "*\\Microsoft\\Cryptography\\Providers\\Trust\\FinalPolicy\\*"
) and
registry.value : ("Dll", "FuncName", "$DLL", "$Function") and
event.type : ("change", "creation")Detects modifications or creation of registry values (Dll, FuncName, $DLL, $Function) under SIP and Trust Provider registry paths used by WinVerifyTrust. These paths control which DLL and function are invoked during Authenticode signature validation. Adversaries overwrite these values to redirect signature checks to malicious DLLs, bypassing AppLocker, WDAC, and SmartScreen enforcement.
Data Sources
Required Tables
False Positives & Tuning
- Legitimate third-party PKI or code-signing software (e.g. DigiCert KeyLocker, Entrust Security Manager) registering custom SIP providers for proprietary file formats during installation
- Software development SDKs that register custom Authenticode SIP handlers for non-standard binary container formats as part of normal build toolchain setup
- Enterprise security products or HSM vendor software updating their own cryptographic validation DLL registrations during patching or version upgrades
Other platforms for T1553.003
Testing Methodology
Validate this detection against 3 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 1SIP CryptSIPDllVerifyIndirectData Hijack — PE SIP Verify Function Override
Expected signal: Sysmon Event ID 13 (Registry Value Set): Two sequential events with TargetObject = HKLM\SOFTWARE\Microsoft\Cryptography\OID\EncodingType 0\CryptSIPDllVerifyIndirectData\{C689AAB8-8E78-11D0-8C47-00C04FC295EE}\Dll and ...\FuncName. Details field shows C:\Windows\System32\ntdll.dll and DbgUiContinue respectively. Image=C:\Windows\System32\WindowsPowerShell\v1.0\powershell.exe. DeviceRegistryEvents in MDE: ActionType=RegistryValueSet, InitiatingProcessFileName=powershell.exe.
- Test 2SIP CryptSIPDllGetSignedDataMsg Hijack via reg.exe — PE SIP Certificate Retrieval Override
Expected signal: Sysmon Event ID 1 (Process Create): reg.exe with CommandLine containing 'CryptSIPDllGetSignedDataMsg' and '/v Dll'. Sysmon Event ID 13 (Registry Value Set): Two events for the Dll and FuncName values under CryptSIPDllGetSignedDataMsg\{C689AAB8...}, Details shows ntdll.dll and DbgPrintEx. Security Event ID 4688 (if command line auditing enabled): reg.exe process creation with command line. DeviceProcessEvents in MDE: FileName=reg.exe with full command line.
- Test 3Trust Provider FinalPolicy Registry Hijack — Software Publishing Trust Provider
Expected signal: Sysmon Event ID 13 (Registry Value Set): Two sequential events with TargetObject = HKLM\SOFTWARE\Microsoft\Cryptography\Providers\Trust\FinalPolicy\{00AAC56B-CD44-11D0-8CC2-00C04FC295EE}\$DLL and ...\$Function. Details field shows C:\Windows\System32\ntdll.dll and DbgUiContinue. Image=powershell.exe. DeviceRegistryEvents in MDE: RegistryKey contains Trust\FinalPolicy, RegistryValueName=$DLL and $Function, ActionType=RegistryValueSet.
References (10)
- https://attack.mitre.org/techniques/T1553/003/
- https://specterops.io/assets/resources/SpecterOps_Subverting_Trust_in_Windows.pdf
- https://github.com/mattifestation/PoCSubjectInterfacePackage
- https://msdn.microsoft.com/library/windows/desktop/aa388208.aspx
- https://msdn.microsoft.com/library/ms537359.aspx
- https://blogs.technet.microsoft.com/eduardonavarro/2008/07/11/sips-subject-interface-package-and-authenticode/
- https://docs.microsoft.com/windows-hardware/drivers/install/catalog-files
- https://docs.microsoft.com/previous-versions/windows/it-pro/windows-server-2008-R2-and-2008/dd941614(v=ws.10)
- https://github.com/redcanaryco/atomic-red-team/blob/master/atomics/T1553.003/T1553.003.md
- https://learn.microsoft.com/en-us/sysinternals/downloads/sigcheck
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