BIOS Revoked-Version Lists for Blocking Vulnerable Rollbacks
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Solution Overview
Problem
Existing information handling systems face the risk of firmware rollback to vulnerable versions, allowing attackers to exploit security flaws by downgrading firmware, which previous systems fail to prevent effectively.
Innovation Solution
Implementing a protected memory with a revoked versions list and a BIOS that scans for and prevents firmware updates to known vulnerable versions, adding entries to the list to block such rollbacks, and allowing users to immediately revoke vulnerable firmware using private keys.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If firmware update is allowed without version verification, then firmware can be updated freely, but system security deteriorates due to rollback attacks
Solution Approach 1:
The patent implements a revoked versions list that is pre-populated with known vulnerable firmware versions before the update process begins. The BIOS scans this list during firmware initialization to prevent updates to vulnerable versions, applying the preliminary action principle by preparing security checks in advance rather than reacting to threats after they occur.
Solution Approach 2:
The patent introduces a revoked versions list as an intermediary data structure that mediates between the firmware update request and the actual update execution. This list acts as a filter or gatekeeper, allowing legitimate updates while blocking updates to vulnerable versions, thus resolving the contradiction between free updates and security without requiring complex verification mechanisms.
2Reliability
If firmware version scanning is implemented, then rollback attacks are prevented, but update process time increases
Solution Approach 1:
The patent implements a scanning mechanism that checks only the firmware version against the revoked versions list, rather than performing comprehensive security audits or full system verification. This partial action approach provides sufficient rollback prevention while minimizing the time penalty, as it focuses only on the critical version check rather than exhaustive validation.
3Reliability
If revoked versions list is maintained, then vulnerable firmware is blocked, but memory usage increases
Solution Approach 1:
The patent implements a revoked versions list that can be easily updated and replaced as new vulnerabilities are discovered. Rather than maintaining a permanent, immutable security database, the system uses a flexible list that can be refreshed with minimal overhead, treating the security database as a disposable resource that is replaced rather than permanently stored.
Data Source
AI summary
An information handling system includes multiple components including a first component. The first component includes a protected memory and a basic input/output system (BIOS). The protected memory stores a revoked versions list. The BIOS initializes a firmware update for a firmware image having a firmware version. The BIOS scans the revoked versions list for the firmware version of the firmware image. In response to the firmware version not being located within the revoked versions list, the BIOS completes the firmware update, and determines whether a revoked firmware version is included in the firmware update. In response to the revoked firmware version being included in the firmware update, the BIOS adds an entry in the revoked versions list. The entry is associated with the revoked firmware version included in the firmware update.