CVE-2021-3601

Related Vulnerabilities: CVE-2021-3601  

No description is available for this CVE.

Description

No description is available for this CVE.

Statement

It was found that OpenSSL will accept a certificate with explicitly set Basic Constraints to CA:FALSE as a valid CA if it is present in the trusted bundle. The exploitability of this bug is limited; the attacker needs to get access to a private key of which the corresponding certificate is in the trust bundle. The attacker is able to leverage this certificate to MITM any connection from the victim machine, not just ones to the specific server that uses the self-signed certificate.

It was found that OpenSSL will accept a certificate with explicitly set Basic Constraints to CA:FALSE as a valid CA if it is present in the trusted bundle. The exploitability of this bug is limited; the attacker needs to get access to a private key of which the corresponding certificate is in the trust bundle. The attacker is able to leverage this certificate to MITM any connection from the victim machine, not just ones to the specific server that uses the self-signed certificate.

Mitigation

Red Hat recommends not to include self-signed server certificates in system trust bundle, even with CA:FALSE, as they are considered full-fledged Certificate Authorities.

Additional Information

  • Bugzilla 1970201: CVE-2021-3601 openssl: Certificate with CA:FALSE is accepted as valid CA cert
  • CWE-295: Improper Certificate Validation
  • FAQ: Frequently asked questions about CVE-2021-3601