cve/2017/CVE-2017-11424.md

CVE-2017-11424

Description

In PyJWT 1.5.0 and below the invalid_strings check in HMACAlgorithm.prepare_key does not account for all PEM encoded public keys. Specifically, the PKCS1 PEM encoded format would be allowed because it is prefaced with the string -----BEGIN RSA PUBLIC KEY----- which is not accounted for. This enables symmetric/asymmetric key confusion attacks against users using the PKCS1 PEM encoded public keys, which would allow an attacker to craft JWTs from scratch.

POC

Reference

No PoCs from references.

Github

• https://github.com/CompassSecurity/security_resources
• https://github.com/aymankhder/security_resources
• https://github.com/silentsignal/rsa_sign2n