Ruby OpenSSL Library X.509 Certificate Bypass Vulnerability [CVE-2018-16395]

CVE Number – CVE-2018-16395

A vulnerability in the OpenSSL library in Ruby could allow an unauthenticated, remote attacker to bypass security restrictions on a targeted system.The vulnerability exists because the affected software insufficiently verifies X.509 certificates when two OpenSSL::X509::Name objects are compared using ==. An attacker could exploit this vulnerability by sending a custom X.509 certificate to the affected system. A successful exploit could allow an attacker to bypass security restrictions on a targeted device.The vendor has confirmed this vulnerability and released software updates.


  • To exploit this vulnerability, the attacker must send a custom X.509 certificate to the targeted system, making exploitation more difficult in environments that restrict network access from untrusted sources.


  • Administrators are advised to apply the appropriate updates.Administrators are advised to allow only trusted users to have network access.Administrators are advised to run both firewall and antivirus applications to minimize the potential of inbound and outbound threats.Administrators may consider using IP-based access control lists (ACLs) to allow only trusted systems to access the affected systems.Administrators can help protect affected systems from external attacks by using a solid firewall strategy.Administrators are advised to monitor affected systems.

Vendor Announcements

Fixed Software

  • The vendor has released software updates at the following link: Download Ruby

Duncan Newell

Duncan is a technology professional with over 20 years experience of working in various IT roles. He has a interest in cyber security, and has a wide range of other skills in radio, electronics and telecommunications.

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