A flaw in Polkit that has been running on Linux systems for seven years allows underprivileged users to access Root.
Malicious users can take advantage of a flaw in Polkit and locally bypass the rights of an unauthorized user to gain root access to the Linux system.
The Polkit (formerly PolicyKit) is a toolkit for setting and manipulating licenses in Linux distributions and is used to allow privileged processes to communicate with privileged processes.
The vulnerability was named CVE-2021-3560 (CVSS rating: 7,8), and affects polkit versions between 0.113 and 0.118. It was discovered by security investigator Kevin Backhouse, who said the issue was raised in code that was first released on November 9, 2013 (!!).
Red Hat Cedric Buissart he mentioned that Debian-based distributions contain polkit 0.105 and are therefore vulnerable.
RHEL 8, Fedora 21 (or later), Debian "Bullseye" and Ubuntu 20.04 are some of the most popular Linux distributions affected by polkit vulnerabilities. The problem has been mitigated in version 0.119, which was released on June 3rd.
Backhouse said: "Vulnerability is surprisingly easy to exploit. All you need is some commands in the terminal using only standard tools like bash, kill and dbus-send.
"Dbus-send" is a Linux inter-process communication (IPC) mechanism used to send messages to the D-Bus messaging bus, allowing communication between multiple processes running on the same computer at the same time. If someone kills the command, it bypasses the authentication because the polkit handles the abruptly terminated message and treats the request as if it came from a root privileged process (UID 0), thus allowing the request.
Linux users should update their operating system immediately to rectify the potential risk arising from the defect.