Anti-patterns for cryptographic signing

Ignoring key compromise: Key compromise can severely affect the integrity of the software. When cryptographic signing keys are suspected to be compromised, immediate steps should be taken to revoke and replace them to maintain the security and trust in the code base. Regular key rotation prevents prolonged unauthorized access from a compromised key and strengthens overall security.

Reuse of signing keys across projects: Sharing the same signing keys across multiple projects also can affect the integrity of the software. If a key is compromised, all projects signed with that key become potential targets. To mitigate the risk, the best practice is to use distinct keys for different projects or workloads.

Incomplete signature verification: Trusting incorrectly signed code can introduce vulnerabilities. Skipping the validation of cryptographic signatures for third-party libraries or dependencies jeopardizes application security. You should consistently validate signatures to maintain code integrity and authenticity. It is equally important to assess certificate attributes such as validity periods and key usage. Avoid relying exclusively on manual checks for signature validation; human oversight in this process is a risk. Using automation in the verification process upholds consistent security checks and minimizes errors.

Overlooking timestamp validation: Ignoring timestamp validation can lead to situations where code is deemed untrustworthy due to an expired certificate, even if the code itself is legitimate and unaltered. This may result in unintentional outages or service disruptions, as systems might refuse to run or integrate with the signed artifact. Proper timestamp validation ensures that certificates were valid at the time the code was signed, preventing unnecessary disruptions due to expired certificates while still maintaining trust in the code's integrity.

Avoid certificate pinning: Hard-coding certificate information within your software, often called certificate pinning, might initially seem like an extra layer of security by tightly coupling your code to a certificate. However, it is an anti-pattern as it makes your software inflexible and brittle. If the pinned certificate needs to be replaced or updated, it will require a software update, which might not be feasible, especially for critical systems or widely distributed applications. Instead, rely on proper certificate validation processes and maintain a flexible and agile certificate management system.