Executive Summary
SIP and Trust Provider Hijacking (T1553.003) is a MITRE ATT&CK technique associated with Defense Impairment. Adversaries may tamper with SIP and trust provider components to mislead the operating system and application control tools when conducting signature validation checks.
Why Attackers Use It
Attackers use SIP and Trust Provider Hijacking because it provides a reliable way to advance their objective within the Defense Impairment tactic, often with a favorable balance of impact versus detectability on Windows environments. Defenders should assess this behavior in the context of the affected platform and adjacent activity rather than treating it as a standalone indicator.
MITRE Description
Adversaries may tamper with SIP and trust provider components to mislead the operating system and application control tools when conducting signature validation checks. In user mode, Windows Authenticode (Citation: Microsoft Authenticode) digital signatures are used to verify a file's origin and integrity, variables that may be used to establish trust in signed code (ex: a driver with a valid Microsoft signature may be handled as safe). The signature validation process is handled via the WinVerifyTrust application programming interface (API) function, (Citation: Microsoft WinVerifyTrust) which accepts an inquiry and coordinates with the appropriate trust provider, which is responsible for validating parameters of a signature. (Citation: SpectorOps Subverting Trust Sept 2017)
Because of the varying executable file types and corresponding signature formats, Microsoft created software components called Subject Interface Packages (SIPs) (Citation: EduardosBlog SIPs July 2008) to provide a layer of abstraction between API functions and files. SIPs are responsible for enabling API functions to create, retrieve, calculate, and verify signatures. Unique SIPs exist for most file formats (Executable, PowerShell, Installer, etc., with catalog signing providing a catch-all (Citation: Microsoft Catalog Files and Signatures April 2017)) and are identified by globally unique identifiers (GUIDs). (Citation: SpectorOps Subverting Trust Sept 2017)
Similar to Code Signing, adversaries may abuse this architecture to subvert trust controls and bypass security policies that allow only legitimately signed code to execute on a system. Adversaries may hijack SIP and trust provider components to mislead operating system and application control tools to classify malicious (or any) code as signed by: (Citation: SpectorOps Subverting Trust Sept 2017)
- Modifying the <code>Dll</code> and <code>FuncName</code> Registry values in <code>HKLM\SOFTWARE[\WOW6432Node]Microsoft\Cryptography\OID\EncodingType 0\CryptSIPDllGetSignedDataMsg{SIP_GUID}</code> that point to the dynamic link library (DLL) providing a SIP’s CryptSIPDllGetSignedDataMsg function, which retrieves an encoded digital certificate from a signed file. By pointing to a maliciously-crafted DLL with an exported function that always returns a known good signature value (ex: a Microsoft signature for Portable Executables) rather than the file’s real signature, an adversary can apply an acceptable signature value to all files using that SIP (Citation: GitHub SIP POC Sept 2017) (although a hash mismatch will likely occur, invalidating the signature, since the hash returned by the function will not match the value computed from the file).
- Modifying the <code>Dll</code> and <code>FuncName</code> Registry values in <code>HKLM\SOFTWARE[WOW6432Node]Microsoft\Cryptography\OID\EncodingType 0\CryptSIPDllVerifyIndirectData{SIP_GUID}</code> that point to the DLL providing a SIP’s CryptSIPDllVerifyIndirectData function, which validates a file’s computed hash against the signed hash value. By pointing to a maliciously-crafted DLL with an exported function that always returns TRUE (indicating that the validation was successful), an adversary can successfully validate any file (with a legitimate signature) using that SIP (Citation: GitHub SIP POC Sept 2017) (with or without hijacking the previously mentioned CryptSIPDllGetSignedDataMsg function). This Registry value could also be redirected to a suitable exported function from an already present DLL, avoiding the requirement to drop and execute a new file on disk.
- Modifying the <code>DLL</code> and <code>Function</code> Registry values in <code>HKLM\SOFTWARE[WOW6432Node]Microsoft\Cryptography\Providers\Trust\FinalPolicy{trust provider GUID}</code> that point to the DLL providing a trust provider’s FinalPolicy function, which is where the decoded and parsed signature is checked and the majority of trust decisions are made. Similar to hijacking SIP’s CryptSIPDllVerifyIndirectData function, this value can be redirected to a suitable exported function from an already present DLL or a maliciously-crafted DLL (though the implementation of a trust provider is complex).
- Note: The above hijacks are also possible without modifying the Registry via DLL search order hijacking.
Hijacking SIP or trust provider components can also enable persistent code execution, since these malicious components may be invoked by any application that performs code signing or signature validation. (Citation: SpectorOps Subverting Trust Sept 2017)
Attack Flow
- Attacker gains the prerequisite access or context described below.
- Attacker executes SIP and Trust Provider Hijacking to achieve its tactical objective (Defense Impairment).
- Resulting access/data/effect is leveraged to advance the broader attack chain (see Related Techniques).
Prerequisites
- Platform(s): Windows
- ATT&CK does not define one universal permission requirement for this technique. Establish the required access from the observed implementation and affected platform.
Common Tools
- Tool attribution is implementation-specific. Use ATT&CK procedure examples and local telemetry to identify the binaries, services, scripts, accounts, or cloud resources involved.
Commands
No universal command represents SIP and Trust Provider Hijacking. Capture the exact command line, arguments, parent process, account, host, and execution time from the investigated environment; do not operationalize unverified examples.
Network Traffic
- Network observability is implementation-dependent. Review DNS, proxy, firewall, flow, authentication, and packet telemetry around the activity window, then correlate remote endpoints and protocol behavior with host evidence.
Windows Events
| Event ID | Log Channel | What It Indicates |
|---|
| Environment-specific | Relevant Windows channel(s) | Correlate authentication, process, object-access, and configuration events with the observed execution context. |
Sysmon Events
| Sysmon Event ID | Name | Why It's Relevant Here |
|---|
| Environment-specific | Validate configured telemetry | Use process, network, file, registry, DNS, or image-load telemetry only when relevant and enabled. |
Detection Opportunities
No MITRE detection guidance published for this technique.
Relevant ATT&CK Data Sources: N/A
Sigma Rules
A universal Sigma rule would create unreliable results because this technique has no single guaranteed observable. Build detection logic from a documented behavior and supported data source, scope it to the affected platform, and validate it against benign administrative activity before deployment.
Splunk Queries
Start with the data sources named in the detection section. Scope searches by asset, identity, and time window; correlate the primary behavior with preceding access and subsequent actions. A portable query is intentionally not provided where the technique lacks a universal schema or observable.
Investigation Workflow
- Confirm that the observed behavior is consistent with SIP and Trust Provider Hijacking and rule out expected administrative or application activity.
- Establish the first-seen time, initiating identity, source system, target system, and affected resources.
- Collect relevant host, identity, network, cloud, and application telemetry for the surrounding time window.
- Correlate parent and child activity, remote connections, file or configuration changes, and related ATT&CK techniques.
- Determine scope by searching for the same observable across peer assets and identities.
- Preserve volatile evidence and record confidence, assumptions, and telemetry gaps before containment.
Containment
- Isolate affected host(s)/account(s) identified during investigation.
- Revoke or rotate any credentials/tokens potentially exposed.
- Apply the mitigations listed below where not already enforced.
- Validate no related techniques (see Related Techniques) were chained against the same asset.
Mitigation
- M1038 -- Execution Prevention: Prevent the execution of unauthorized or malicious code on systems by implementing application control, script blocking, and other execution prevention mechanisms.
- M1024 -- Restrict Registry Permissions: Restricting registry permissions involves configuring access control settings for sensitive registry keys and hives to ensure that only authorized users or processes can make modifications.
- M1022 -- Restrict File and Directory Permissions: Restricting file and directory permissions involves setting access controls at the file system level to limit which users, groups, or processes can read, write, or execute files.
Related Techniques