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Security advisories — Jan 26, 2022

Polkit Vulnerability Impacting Linux Devices 

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On January 25th, 2022, a new vulnerability impacting Polkit’s pkexec program was disclosed. Polkit’s pkexec is included by default in all major Linux distributions. The vulnerability is tracked as CVE-2021-4034 (CVSS: 7.8) and allows for Local Privilege Escalation. Exploitation would enable a threat actor, with previous access to a vulnerable device, to escalate their privileges to full root privileges.

Exploitation of CVE-2021-4034 has not been identified at this time. eSentire has confirmed that functioning Proof-of-Concept exploit code is publicly available. Organizations are strongly encouraged to ensure that impacted systems are patched as soon as possible, as exploitation is expected in the immediate future.

What we’re doing about it

What you should do about it

Additional information

Polkit’s pkexec is used to control system-wide privileges in Linux operating systems. It is meant to allow authorized users to run commands as the super user.

Exploitation has been tested and confirmed against Ubuntu, Debian, Fedora, and CentOS Linux distributions. Each impacted Linux distribution will be required to release their own updates to address CVE-2021-4034. Vendor responses can be found in the following links:

This list is expected to expand as distributions address CVE-2021-4034.

Exploits for CVE-2021-4034 are being widely shared by both researchers and threat actors. eSentire assesses, with high confidence, that this vulnerability will be adopted by threat actors for real world exploitation in a matter of days.


[1] https://blog.qualys.com/vulnerabilities-threat-research/2022/01/25/pwnkit-local-privilege-escalation-vulnerability-discovered-in-polkits-pkexec-cve-2021-4034
[2] https://linux.die.net/man/1/pkexec
[3] https://access.redhat.com/security/cve/CVE-2021-4034
[4] https://ubuntu.com/security/CVE-2021-4034
[5] https://security-tracker.debian.org/tracker/CVE-2021-4034

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