iPXE Script Validation via Owner Certificates and TPM
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Solution Overview
Problem
The challenge lies in securely verifying and validating open-source iPXE scripts during the pre-boot execution process, particularly in co-location deployments where network devices must ensure they boot from their intended service provider's network, as untrusted scripts can lead to security threats and unauthorized booting from hacked servers.
Innovation Solution
The solution involves using owner certificates and ownership vouchers, anchored on network devices with unique device identifiers, to validate and verify iPXE scripts before execution. This process includes storing these certificates in a trusted platform module (TPM) and utilizing a manufacturer-authorized signing authority server to ensure only signed, device-specific scripts are executed, preventing booting from unauthorized networks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If untrusted iPXE scripts are executed during pre-boot, then device booting can proceed quickly, but security is compromised allowing unauthorized access and chain loading of non-signed images
Solution Approach 1:
The system performs preliminary verification of iPXE scripts by checking owner certificates and ownership vouchers before execution. The verification process validates that the script is signed by the authorized owner and has not been tampered with, preventing security threats before they can manifest during boot execution.
Solution Approach 2:
The patent introduces owner certificates and ownership vouchers as intermediary verification mechanisms. These certificates act as trusted intermediaries that bridge the gap between the iPXE script and the device's trusted platform module, enabling secure verification without requiring direct trust in the script source.
2Adaptability or versatility
If manufacturer certificates are used to sign iPXE scripts, then verification can be performed, but device-specific customization is lost as manufacturers cannot sign owner-created scripts
Solution Approach 1:
The system implements local quality by allowing each device to have its own owner certificate stored in the trusted platform module. This enables device-specific customization where each owner can create and sign their own iPXE scripts, while the verification process maintains trust by checking against the device's unique owner certificate rather than a generic manufacturer certificate.
Solution Approach 2:
The patent enables self-service by allowing device owners to create their own owner certificates and sign their iPXE scripts independently. The owner's private key is stored in the trusted platform module, enabling the owner to self-sign scripts without requiring manufacturer intervention, while the verification process uses the corresponding public key from the owner certificate.
3Adaptability or versatility
If iPXE scripts are downloaded from external sources, then boot options can be extended, but the threat surface increases allowing execution of malicious scripts from hacked servers
Solution Approach 1:
The system applies preliminary anti-action by implementing a verification mechanism that blocks execution of malicious scripts before they can cause harm. The owner certificate verification process acts as a preventive measure, rejecting any script that cannot be verified against the device's trusted owner certificate, thereby countering potential attacks from hacked servers or unauthorized sources.
Data Source
AI summary
Techniques and architecture are described for validating and verifying iPXE scripts prior to execution during a booting process. During the booting process of a network device, right after the UEFI/BIOS stage of the booting process, a trusted iPXE script may make a request to a network server for the ownership voucher and owner certificate of the network device. The ownership voucher and owner certificate may then be stored in a trusted platform module (TPM) on the network device. In configurations, the retrieved owner certificate may be validated by the ownership voucher. The owner certificate may be used to validate iPXE scripts. Once validated, the iPXE scripts may be executed and the booting process may be continued to the kernel loading step and the application loading step. During a subsequent booting process of the network device, the ownership voucher and owner certificate may be retrieved from the TPM.