Detect SIP and Trust Provider Hijacking in CrowdStrike LogScale
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 $Function values under HKLM\SOFTWARE\Microsoft\Cryptography\Providers\Trust\FinalPolicy\{GUID}. This allows malicious or unsigned code to appear validly signed to application whitelisting tools, AppLocker, WDAC, and SmartScreen. Because SIP components are invoked by any process performing signature validation, hijacking them also provides persistent code execution opportunities.
MITRE ATT&CK
- Tactic
- Defense Evasion
- Technique
- T1553 Subvert Trust Controls
- Sub-technique
- T1553.003 SIP and Trust Provider Hijacking
- Canonical reference
- https://attack.mitre.org/techniques/T1553/003/
LogScale Detection Query
#event_simpleName = RegGenericValueUpdate
| RegObjectName = /(?i)(CryptSIPDllGetSignedDataMsg|CryptSIPDllVerifyIndirectData|Trust\\FinalPolicy)/
| RegValueName = /(?i)^(Dll|FuncName|\$DLL|\$Function)$/
| SIPType := if(RegObjectName = /(?i)CryptSIPDllGetSignedDataMsg/, "SIP-GetSignedDataMsg",
if(RegObjectName = /(?i)CryptSIPDllVerifyIndirectData/, "SIP-VerifyIndirectData",
if(RegObjectName = /(?i)Trust\\FinalPolicy/, "TrustProvider-FinalPolicy", "Unknown")))
| IsWow64 := if(RegObjectName = /WOW6432Node/, "true", "false")
| IsNonSystemDll := if(RegStringValue = /(?i)(windows\\system32|windows\\syswow64|wintrust\.dll|mssip32\.dll)/, "false", "true")
| table([@timestamp, ComputerName, UserName, ImageFileName, CommandLine, RegObjectName, RegValueName, RegStringValue, SIPType, IsWow64, IsNonSystemDll])
| sort(field=@timestamp, order=desc)CrowdStrike LogScale CQL query detecting RegGenericValueUpdate Falcon telemetry events targeting SIP and Trust Provider registry paths. Filters on writes to Dll, FuncName, $DLL, and $Function value names under Microsoft Cryptography OID and Trust FinalPolicy keys. Enriches matches with SIP component classification, WOW64 node detection, and a flag for DLL paths outside trusted Windows system directories to surface the highest-fidelity alerts.
Data Sources
Required Tables
False Positives & Tuning
- Legitimate software installations that register custom Authenticode SIP providers, such as PDF signing software (Adobe Acrobat), Office document signing tools, or specialized PKI client software writing DLL paths to non-system locations that are still trusted
- CrowdStrike Falcon sensor self-updates or other endpoint security agents modifying their own cryptographic validation registry entries as part of integrity verification during version upgrades
- Enterprise software deployment systems (SCCM, Intune, Ansible) pushing updates to certificate management components that legitimately extend or replace SIP provider DLL registrations across a fleet
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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