CVE-2016-9121 in go-jose
Summary
by MITRE
go-jose before 1.0.4 suffers from an invalid curve attack for the ECDH-ES algorithm. When deriving a shared key using ECDH-ES for an encrypted message, go-jose neglected to check that the received public key on a message is on the same curve as the static private key of the receiver, thus making it vulnerable to an invalid curve attack.
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Analysis
by VulDB Data Team • 11/22/2022
The vulnerability identified as CVE-2016-9121 affects the go-jose library version 1.0.3 and earlier, specifically within the ECDH-ES (Elliptic Curve Diffie-Hellman Ephemeral Static) key agreement algorithm implementation. This flaw represents a critical security weakness that undermines the cryptographic integrity of encrypted communications. The issue stems from improper validation of elliptic curve parameters during key derivation processes, creating a pathway for attackers to exploit the cryptographic system through what is known as an invalid curve attack.
The technical flaw manifests when the ECDH-ES algorithm processes encrypted messages containing public keys that do not conform to the expected elliptic curve parameters used by the recipient's static private key. In a properly implemented cryptographic system, the receiver should validate that any received public key exists on the same elliptic curve as the private key being used for key derivation. The go-jose library failed to perform this crucial validation step, allowing malicious actors to submit public keys that lie on different curves, potentially enabling them to recover the shared secret key used for encryption.
This vulnerability directly relates to CWE-327, which addresses the use of weak cryptographic algorithms and improper implementation of cryptographic functions. The attack vector specifically targets the elliptic curve discrete logarithm problem by exploiting the mathematical properties of elliptic curves, allowing an attacker to potentially decrypt messages without proper authorization. The operational impact is severe as it compromises the confidentiality of encrypted communications, making the system vulnerable to passive eavesdropping and active man-in-the-middle attacks.
The security implications extend beyond simple data exposure, as this vulnerability enables attackers to potentially impersonate legitimate parties within the encrypted communication framework. When an invalid curve attack succeeds, it allows adversaries to derive the shared secret key used in the ECDH-ES process, effectively breaking the encryption and enabling decryption of sensitive information. This weakness particularly affects systems relying on JWT (JSON Web Tokens) and other cryptographic protocols that utilize the go-jose library for secure key exchange operations.
Organizations using affected versions of go-jose should immediately implement mitigations including upgrading to version 1.0.4 or later, which includes proper curve validation checks. Additionally, system administrators should review their cryptographic implementations for similar validation weaknesses and consider implementing additional monitoring for anomalous key exchange patterns. The fix addresses the core issue by ensuring that all received public keys undergo rigorous curve parameter validation before being used in key derivation processes, aligning with established cryptographic best practices and NIST guidelines for elliptic curve cryptography implementation.
From an attack framework perspective, this vulnerability maps to several ATT&CK techniques including T1566 for credential access through cryptographic attacks and T1046 for network service scanning that may reveal vulnerable systems. The attack requires minimal computational resources and can be automated, making it particularly dangerous in large-scale deployments where multiple systems may be simultaneously vulnerable. Security teams should prioritize patching this vulnerability and conduct thorough audits of cryptographic libraries used throughout their infrastructure to prevent similar issues from arising in other components.