Server Certificate Validation Through OCSP Stapling

OWASP 2013-A5 OWASP 2017-A6 OWASP 2021-A5 CWE-299 WASC-13

SSL Certificates are data files that bind a cryptographic key. There are servers that uses vulnerable versions of openSSL. This may lead to OCSP stapling vulnerability. The old versions of OpenSSL allow remote attackers to successfully attempt a denial of service. The attacker can also possibly get sensitive information in a web application. This can be done by using a vulnerable/improper ClientHello handshake message. This message will trigger out-of-bounds memory access.


The impact include:-

  • Denial of service
  • OCSP Stapling

Mitigation / Precaution

This vulnerability can be fixed by:-

  • Updating the OpenSSL to Latest version
  • Upgrading the version
  • If it is not immediately possible, patch the source code for OCSP Stapling

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