Secure System Service Redirection via Provider Tables
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Solution Overview
Problem
Current methods for intercepting system service calls, such as 'hooking' system service tables, are unsafe, unsupported, and unsecure, posing significant security risks due to difficulties in verifying redirected service call targets and preventing data structure modifications.
Innovation Solution
The implementation of secured system service redirection technology that dynamically and securely loads verified service call providers into the operating system, allowing them to register alternate service tables and reroute system service calls in a secure manner using virtualization-based security to validate and maintain provider service tables.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If system service tables are hooked to intercept system service calls, then system call monitoring and filtering capabilities are improved, but security risks increase due to inability to verify redirected targets and prevent data structure modifications
Solution Approach 1:
The patent introduces a secure service call provider as an intermediary between the system service table and the actual service implementation. This provider acts as a verified mediator that safely intercepts and redirects system service calls, eliminating the need for direct hooking into the system service table while maintaining monitoring and filtering capabilities.
Solution Approach 2:
The patent segments the system into distinct trust zones (higher trust security zone for secure operating system, lower trust security zone for user-mode processes). By separating the secure service call provider from the untrusted hooking mechanism, the system achieves both functionality and security through spatial segmentation of trust levels.
2Adaptability or versatility
If standard system service tables are modified to redirect service calls, then service call routing flexibility is improved, but system stability deteriorates due to potential corruption and abuse
Solution Approach 1:
The patent extracts the redirection functionality from the system service table itself and places it in a separate secure service call provider. This removes the harmful modification aspect from the system service table while preserving the useful redirection capability in the extracted provider component.
Solution Approach 2:
The patent creates a copy of the service table functionality in the form of a provider service table that operates under security constraints. Instead of modifying the original system service table, a secure copy is created that implements redirection through verified providers, maintaining the original table's integrity.
3Adaptability or versatility
If dynamic service call providers are loaded to provide value-add services, then system functionality is improved, but security verification complexity increases
Solution Approach 1:
The patent applies preliminary verification through digital signatures when service call providers are loaded. The secure operating system verifies the provider's authenticity and authority before allowing it to redirect service calls, performing security validation in advance rather than during execution.
Solution Approach 2:
The patent implements a feedback mechanism where the secure operating system continuously monitors and validates service call provider operations. The system provides feedback about provider performance and security compliance, enabling dynamic adjustment and revocation of provider privileges based on observed behavior.
Data Source
AI summary
Securely redirecting a system service routine via a provider service table. A service call provider is loaded within an operating system executing in a lower trust security zone. The service call provider comprises metadata indicating a system service routine to be redirected to the service call provider. Based on the metadata, a provider service table is built within a higher trust security zone. The service table redirects the system service routine to the service call provider. Memory page(s) associated with the provider service table are hardware protected, and a read-only view is exposed to the operating system. The provider service table is associated with a user-mode process. A service call for a particular system service routine is received by the operation system from the user-mode process and, based on the provider service table being associated with the user-mode process, the service call is directed to the service call provider.