UEFI Variable Key Exchange for Secure Remote Management
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Solution Overview
Problem
Current Information Handling Systems (IHS) face challenges in securely managing remote administration due to the complexity of establishing trust between client software programs and remote management tools, particularly in data center environments where secure communications are crucial.
Innovation Solution
The implementation of a secured data storage device with UEFI variables, a processor that generates a keypair, and a BIOS that encrypts and writes a remote management secret to these variables, allowing for a secure remote management session between the client management application and the remote access controller, utilizing Redfish protocols and validating firmware and client management application signatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional remote management methods are used, then remote administration capability is provided, but security and trust establishment between client software and remote management tools becomes complex and vulnerable
Solution Approach 1:
The system performs preliminary actions by generating cryptographic key pairs and establishing trust relationships before remote management operations begin. The client management application generates a key pair and stores the public key in UEFI variables, while the remote management tool obtains the private key during provisioning, creating a secure foundation before actual remote management occurs.
Solution Approach 2:
UEFI variables serve as a trusted intermediary between the client management application and the remote management tool. The public key is stored in protected UEFI variables, which act as a secure mediator that enables authentication without requiring direct trust establishment between the two parties. The BIOS validates firmware and application signatures through this intermediary layer.
2Reliability
If UEFI variables are made accessible for keypair storage and secret encryption, then secure remote management is enabled, but potential security risks from unauthorized access to UEFI variables increases
Solution Approach 1:
The system applies local quality by implementing differentiated access controls for different UEFI variables based on their security requirements. Critical variables such as those storing the remote management secret and public key have restricted access limited to specific privileged components (BIOS, authenticated applications), while other UEFI variables maintain traditional access patterns. This selective security approach protects sensitive data without unnecessarily restricting legitimate access to other system variables.
Solution Approach 2:
The BIOS performs self-service by automatically validating firmware signatures and client management application signatures against reference signatures stored in protected UEFI variables before granting access to write operations. This self-validation mechanism ensures that only authenticated and authorized components can modify critical UEFI variables, providing automatic security enforcement without requiring external intervention.
3Reliability
If signature validation is implemented for BIOS and client management application, then system integrity is ensured, but processing time and operational complexity increase
Solution Approach 1:
The system performs signature validation as a preliminary action during system initialization and before granting write access to UEFI variables. The BIOS validates its own firmware signature and the client management application's signature against reference signatures stored in protected UEFI variables during the boot process and authentication phase. By completing validation beforehand, the system ensures integrity without requiring repeated validation during normal operations.
Data Source
AI summary
Methods and system are provided for remote management of an IHS (Information Handling System). A keypair is generated by a client management application using operating system capabilities of the IHS. The client management application, as a privileged operating system user, writes a public key of the keypair to UEFI (Unified Extensible Firmware Interface) variables stored within a secured data storage device of the IHS. A BIOS of the IHS retrieves the public key from the UEFI variables and uses it to encrypt a remote management secret. The BIOS writes the encrypted secret back to the UEFI variables. The client management application uses the keypair to recover the remote management secret from the encrypted secret that was written to the UEFI variables by the BIOS. The secret is used to establish a secure remote management session between the client management application and a remote access controller of the IHS.