CIRA Canadian Shield iOS Application - MITM SSL Certificate Vulnerability (CVE-2021-27189)


"CIRA Canadian Shield protects you from online threats such as malicious domains, phishing websites and helps to keep your personal data private. It also provides DNS privacy by keeping your DNS requests in Canada. This app works by changing your phone's DNS settings to run your requests through CIRA's Canadian server network."



The Canadian Internet Registration Authority (CIRA) Canadian Shield iOS application (version 4.0.12 and below), does not validate the SSL certificate it receives when connecting to the application server.


An attacker who can perform a man in the middle attack may present a bogus SSL certificate which the application will accept silently. Sensitive information could be captured by an attacker without the user's knowledge.


December 22, 2020 - Attempted to obtain a security contact via a form on
December 23, 2020 - Asked for a security contact via an email to
December 23, 2020 - CIRA support asked for details which they will forward to the right team
December 28, 2020 - Asked for a security contact via an email to
December 30, 2020 - Asked the Canadian Centre for Cyber Security (CCCS) if they could connect me with security contact at CIRA
December 31, 2020 - CCCS responded that they will attempt to connect me with a security contact at CIRA
January 4, 2021 - A security contact at CIRA confirmed that is the correct address to send the details
January 4, 2021 - Provided the details to CIRA via
January 5, 2021 - CIRA confirmed receipt of the details
February 1, 2021 - CIRA confirmed the issue and stated they are working on an update
February 22, 2021 - CIRA released version 4.0.13


Upgrade to version 4.0.13 or later



Thanks to the Canadian Centre for Cyber Security for their assistance

CIRA's Pwnie Nomination For Most Epic Fail




Contact Information