Missing Authentication for Critical Function in Squid - CVE-2019-12524

Vulnerability details

The vulnerability allows a remote attacker to bypass certain security restrictions.

When handling requests from users, Squid checks its rules to see if the request should be denied. Squid by default comes with rules to block access to the Cache Manager, which serves detailed server information meant for the maintainer. This rule is implemented via url_regex. The handler for url_regex rules URL decodes an incoming request. This allows an attacker to encode their URL to bypass the url_regex check, and gain access to the blocked resource.

Affected software

How to mitigate CVE-2019-12524

External References

• https://gitlab.com/jeriko.one/security/-/blob/master/squid/CVEs/CVE-2019-12524.txt
• https://www.debian.org/security/2020/dsa-4682

Related Security Bulletins

• Debian update for squid
• Red Hat Enterprise Linux 8 update for the squid:4 module
• Anolis OS update for squid:4 (Anolis OS 8.4) module
• Ubuntu update for squid3
• Ubuntu update for squid3
• Multiple vulnerabilities in Squid