CWE-1291: Public Key Re-Use for Signing both Debug and Production Code

BaseDraft

The same public key is used for signing both debug and production code.

View on MITRE
Back to CWE Lookup

Extended Description

A common usage of public-key cryptography is to verify the integrity and authenticity of another entity (for example a firmware binary). If a company wants to ensure that its firmware runs only on its own hardware, before the firmware runs, an encrypted hash of the firmware image will be decrypted with the public key and then verified against the now-computed hash of the firmware image. This means that the public key forms the root of trust, which necessitates that the public key itself must be protected and used properly. During the development phase, debug firmware enables many hardware debug hooks, debug modes, and debug messages for testing. Those debug facilities provide significant, additional views about the firmware's capability and, in some cases, additional capability into the chip or SoC. If compromised, these capabilities could be exploited by an attacker to take full control of the system. Once the product exits the manufacturing stage and enters production, it is good practice to use a different public key. Debug firmware images are known to leak. With the debug key being reused as the production key, the debug image will also work on the production image. Thus, it will open all the internal, debug capabilities to the attacker. If a different public key is used for the production image, even if the attacker gains access to the debug firmware image, they will not be able to run it on a production machine. Thus, damage will be limited to the intellectual property leakage resulting from the debug image.

Technical Details

Structure
Simple

Applicable To

Languages
Not Language-Specific
Platforms
Not OS-Specific

Frequently Asked Questions

What is CWE-1291: Public Key Re-Use for Signing both Debug and Production Code?+

CWE-1291: Public Key Re-Use for Signing both Debug and Production Code is a Common Weakness Enumeration (CWE) entry maintained by MITRE. The same public key is used for signing both debug and production code. A common usage of public-key cryptography is to verify the integrity and authenticity of another entity (for example a firmware binary). If a company wants to ensure that its firmware runs only on its own hardware, before the firmware runs, an encrypted hash of the firmware image will be decrypted with the public key and then verified against the now-computed hash of the firmware image. This means that the public key forms the root of trust, which necessitates that the public key itself must be protected and used properly. During the development phase, debug firmware enables many hardware debug hooks, debug modes, and debug messages for testing. Those debug facilities provide significant, additional views about the firmware's capability and, in some cases, additional capability into the chip or SoC. If compromised, these capabilities could be exploited by an attacker to take full control of the system. Once the product exits the manufacturing stage and enters production, it is good practice to use a different public key. Debug firmware images are known to leak. With the debug key being reused as the production key, the debug image will also work on the production image. Thus, it will open all the internal, debug capabilities to the attacker. If a different public key is used for the production image, even if the attacker gains access to the debug firmware image, they will not be able to run it on a production machine. Thus, damage will be limited to the intellectual property leakage resulting from the debug image.

What are the security consequences of Public Key Re-Use for Signing both Debug and Production Code?+

If exploited, CWE-1291 (Public Key Re-Use for Signing both Debug and Production Code) it can compromise Confidentiality, Integrity, Availability, Access Control, Accountability and Authentication, leading to outcomes such as Read Memory, Modify Memory, Execute Unauthorized Code or Commands, Gain Privileges or Assume Identity and Varies by Context.

How do you prevent or mitigate Public Key Re-Use for Signing both Debug and Production Code?+

Recommended mitigations for CWE-1291 include: Use different keys for Production and Debug

How is Public Key Re-Use for Signing both Debug and Production Code detected?+

CWE-1291 can be detected using Architecture or Design Review and Dynamic Analysis with Manual Results Interpretation. Combining automated tooling with manual review typically yields the best coverage.

Which programming languages are affected by Public Key Re-Use for Signing both Debug and Production Code?+

CWE-1291 commonly affects Not Language-Specific. Note that weaknesses are often language-agnostic patterns, so secure coding practices apply broadly.

What is the difference between a CWE and a CVE?+

A CWE (Common Weakness Enumeration) like CWE-1291 describes a category of software weakness — the underlying flaw type. A CVE (Common Vulnerabilities and Exposures) identifies a specific, real-world vulnerability in a particular product. In short, a CWE is the kind of mistake, and a CVE is an instance of that mistake being found in software.

Learn More