A Linux System Service Bug Allows the Root on Modern Distros

A Linux System Service Bug Allows the Root on Modern Distros

Polkit is a system service installed by default on many Linux distributions that are used by systemd, therefore any Linux distribution that uses systemd also uses polkit.

Polkit and Its Importance?

Polkit represents the system that plays the role of a decision-maker tool, as for example, it can decide whether or not you’re allowed to create a new user account.


Polkit is designed to make decisions instantly and also to let an administrator grant authorization for making a decision.

A few weeks ago GitHub Security Lab security researcher Kevin Backhouse found a privilege escalation vulnerability in polkit that enables an unprivileged local user to get a root shell on the system, therefore making it easier to exploit with just a few standard command-line tools.

The polkit local privilege escalation bug was tracked as CVE-2021-3560 after being publicly disclosed and a fix for this specifical vulnerability was released on June 3, 2021.

The bug found was quite old, as it was introduced seven years ago in the commit bfa5036 and shipped with the polkit version 0.113, but as many of the most popular Linux distributions didn’t ship the vulnerable version until more recently.

Linux users: please upgrade polkit to get the fix for CVE-2021-3560. More details in a blog post later this week. https://t.co/NCNY2s6O5g

— Kevin Backhouse (@kevin_backhouse) linux system service allows modern distros