CWE-1283 Detail

The register contents used for attestation or measurement reporting data to verify boot flow are modifiable by an adversary.

A System-on-Chip (SoC) implements secure boot or verified boot. During this boot flow, the SoC often measures the code that it authenticates. The measurement is usually done by calculating the one-way hash of the code binary and extending it to the previous hash. The hashing algorithm should be a Secure One-Way hash function. The final hash, i.e., the value obtained after the completion of the boot flow, serves as the measurement data used in reporting or in attestation. The calculated hash is often stored in registers that can later be read by the party of interest to determine tampering of the boot flow. A common weakness is that the contents in these registers are modifiable by an adversary, thus spoofing the measurement.

Modes Of Introduction

Architecture and Design : Such issues can be introduced during hardware architecture or design and can be identified later during Testing or System Configuration phases.
Implementation : If the access-controls which protecting the reporting registers are misconfigured during implementation, this weakness can arise.

Applicable Platforms

Language

Class: Not Language-Specific (Undetermined)

Operating Systems

Class: Not OS-Specific (Undetermined)

Architectures

Class: Not Architecture-Specific (Undetermined)

Technologies

Class: Not Technology-Specific (Undetermined)

Common Consequences

Potential Mitigations

Phases : Architecture and Design

Measurement data should be stored in registers that are read-only or otherwise have access controls that prevent modification by an untrusted agent.

Vulnerability Mapping Notes

Justification : This CWE entry is at the Base level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.
Comment : Carefully read both the name and description to ensure that this mapping is an appropriate fit. Do not try to 'force' a mapping to a lower-level Base/Variant simply to comply with this preferred level of abstraction.

Related Attack Patterns

NotesNotes

This entry is still in development and will continue to see updates and content improvements.

References

REF-1107

PCIe Device Measurement Requirements
Intel Corporation.
https://www.intel.com/content/dam/www/public/us/en/documents/reference-guides/pcie-device-security-enhancements.pdf

REF-1131

BIOS Chronomancy: Fixing the Core Root of Trust for Measurement
John Butterworth, Cory Kallenberg, Xeno Kovah.
https://media.blackhat.com/us-13/US-13-Butterworth-BIOS-Security-Slides.pdf

Submission

Modifications