CVE-2023-45287 Before Go 1.20, the RSA based key exchange methods in crypto/tls may exhibit a timing side channel

2023-12-0516:18:06

www.cve.org

cve-2023-45287

rsa

key exchange

crypto/tls

timing side channel

go 1.20

7.7 High

AI Score

Confidence

High

0.001 Low

EPSS

Percentile

30.8%

JSON

Before Go 1.20, the RSA based TLS key exchanges used the math/big library, which is not constant time. RSA blinding was applied to prevent timing attacks, but analysis shows this may not have been fully effective. In particular it appears as if the removal of PKCS#1 padding may leak timing information, which in turn could be used to recover session key bits. In Go 1.20, the crypto/tls library switched to a fully constant time RSA implementation, which we do not believe exhibits any timing side channels.

CNA Affected

[
  {
    "vendor": "Go standard library",
    "product": "crypto/tls",
    "collectionURL": "https://pkg.go.dev",
    "packageName": "crypto/tls",
    "versions": [
      {
        "version": "0",
        "lessThan": "1.20.0",
        "status": "affected",
        "versionType": "semver"
      }
    ],
    "programRoutines": [
      {
        "name": "rsaKeyAgreement.processClientKeyExchange"
      },
      {
        "name": "rsaKeyAgreement.generateClientKeyExchange"
      },
      {
        "name": "Conn.Handshake"
      },
      {
        "name": "Conn.HandshakeContext"
      },
      {
        "name": "Conn.Read"
      },
      {
        "name": "Conn.Write"
      },
      {
        "name": "Dial"
      },
      {
        "name": "DialWithDialer"
      },
      {
        "name": "Dialer.Dial"
      },
      {
        "name": "Dialer.DialContext"
      }
    ],
    "defaultStatus": "unaffected"
  }
]