CIRA Canadian Shield iOS Application - MITM SSL Certificate
Vulnerability (CVE-2021-27189)
--
https://www.info-sec.ca/advisories/CIRA-Canadian-Shield.html

Overview

"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."

(https://apps.apple.com/ca/app/cira-canadian-shield/id1499859661)

Issue

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.

Impact

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.

Timeline

December 22, 2020 - Attempted to obtain a security contact via a form on cira.ca
December 23, 2020 - Asked for a security contact via an email to
canadianshield@cira.ca
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
security@cira.ca
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
security@cira.ca is the correct address to send the details
January 4, 2021 - Provided the details to CIRA via security@cira.ca
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

Solution

Upgrade to version 4.0.13 or later

CVE-ID

CVE-2021-27189