An adversary exploits a weakness resulting from using a hashing algorithm with weak collision resistance to generate certificate signing requests (CSR) that contain collision blocks in their "to be signed" parts. The adversary submits one CSR to be signed by a trusted certificate authority then uses the signed blob to make a second certificate appear signed by said certificate authority. Due to the hash collision, both certificates, though different, hash to the same value and so the signed blob works just as well in the second certificate. The net effect is that the adversary's second X.509 certificate, which the Certification Authority has never seen, is now signed and validated by that Certification Authority.

Related CWE definitions

This attack-focused weakness is caused by incorrectly implemented authentication schemes that are subject to spoofing attacks.
The product does not validate, or incorrectly validates, a certificate.
The product uses a broken or risky cryptographic algorithm or protocol.
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