CRTM Lock Mechanism for Secure BIOS Updates
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Solution Overview
Problem
The challenge is to securely update the Basic Input/Output System (BIOS) while maintaining the immutability of the Core Root of Trust for Measurement (CRTM) to prevent unauthorized modifications, as current BIOS flash methods can be exploited by hackers.
Innovation Solution
Implementing a CRTM update utility that uses a lock function to authenticate and authorize updates, ensuring that only authorized entities can modify the BIOS, by storing a signature in a predefined location and requiring authentication before allowing updates to the CRTM, which includes locking the CRTM unless a valid signature is provided.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If BIOS is made immutable to maintain CRTM integrity, then security is improved, but BIOS updates become impossible
Solution Approach 1:
The patent segments the BIOS into two distinct parts: the CRTM (Core Root of Trust for Measurement) which remains immutable and locked, and the rest of the BIOS which can be updated. This segmentation allows the system to maintain CRTM integrity while enabling necessary BIOS updates through separate update mechanisms for non-CRTM portions.
Solution Approach 2:
The patent implements preliminary locking of the CRTM portion of the BIOS during manufacturing or initial setup. This preliminary action establishes an immutable foundation before the system enters normal operation, ensuring that the critical measurement root cannot be modified even during subsequent BIOS updates.
2Adaptability or versatility
If BIOS is made updateable to fix vulnerabilities, then adaptability is improved, but security against unauthorized modification deteriorates
Solution Approach 1:
The patent divides the BIOS firmware into updateable portions and locked CRTM portions. The updateable portions can be patched and improved while the locked CRTM provides an immutable security anchor that prevents unauthorized modifications, thus maintaining security while enabling updates.
Solution Approach 2:
The patent introduces a lock mechanism as an intermediary between the BIOS update process and the CRTM. This lock acts as a mediator that allows legitimate updates to proceed while blocking unauthorized modifications, thus resolving the security concern while maintaining update capability.
3Ease of operation
If application level flash utilities are used for BIOS updates, then ease of operation is improved, but vulnerability to hacking increases
Solution Approach 1:
The patent introduces a lock mechanism as an intermediary layer between the application-level flash utility and the BIOS firmware. This lock verifies authentication credentials before allowing updates to proceed, thus maintaining the ease of operation provided by high-level utilities while blocking hacker exploitation through the authentication barrier.
Solution Approach 2:
The patent implements preliminary authentication verification through the lock mechanism before allowing any BIOS updates. This preliminary anti-action prevents malicious updates from occurring in the first place, countering potential hacking attempts before they can exploit the flash utility interface.
Data Source
AI summary
A computer system is provided that comprises a processor and a Basic Input/Output System (BIOS) module coupled to the processor. The BIOS module stores a Core Root of Trust for Measurement (CRTM), wherein the CRTM selectively unlocks itself.