nameConstraints

Russian Ministry Certificates Enable Potential State MITM on Foreign Domains

Russian companies facing sanctions have started adopting root certificates issued by the Ministry of Digital Development and Communications to maintain HTTPS access after commercial CAs revoked or refused to renew their certificates. Installing these Ministry certificates allows browsers to trust sites using Russian national CAs but also creates a pathway for man-in-the-middle interception by state-controlled entities. The article details a concrete threat model where a government-linked operator could use the Ministry root to generate on-the-fly certificates for any domain, including foreign services outside Russian jurisdiction. To mitigate this, the author demonstrates how to re-sign the Ministry root with OpenSSL nameConstraints limited to .ru, .su, and .рф domains only. Tests on macOS with Homebrew show that the constrained certificate still validates Russian banking sites such as online.sberbank.ru while correctly rejecting attempts to validate foreign domains like sberbank.com. The technique requires users to maintain their own cross-signed root and never rely on pre-installed Ministry or Yandex Browser roots for full protection.