Before Go 1.20, the RSA based key exchange methods in crypto/tls may exhibit a timing side channel

CVE-2023-45287

What is CVE-2023-45287?

Before version 1.20, the Go programming language employed an RSA-based TLS key exchange mechanism utilizing the math/big library, which was not designed to operate in constant time. Although RSA blinding techniques were introduced to mitigate the risk of timing attacks, investigations indicated that these measures were insufficient. The absence of PKCS#1 padding created opportunities for timing information leaks, potentially allowing attackers to recover bits of the session key. With the release of Go 1.20, a transition to a fully constant time RSA implementation was made within the crypto/tls library, effectively addressing the timing side channels that were present in earlier versions.

References