ThreatRoundup

CVE-2021-4034: Red Hat Polkit (High, CVSS 7.8)

CVE record · updated

CVE-2021-4034HighKEVPublic exploitRed Hat Polkit
CVSS
7.8 High (v3.1)
EPSS
94.9% chance of exploitation in the next 30 days (higher than 99.8% of CVEs)
Exploited in the wild
Yes, on CISA’s KEV list since Jun 27, 2022; used by ransomware
Public exploit
Yes, reported in a Metasploit module, Exploit-DB and 184 GitHub repositories
Weakness
CWE-125, CWE-787
Vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Published
Jan 28, 2022
CISA fix-by date
Jul 18, 2022 (for US federal agencies)

What it is

A local privilege escalation vulnerability was found on polkit's pkexec utility. The pkexec application is a setuid tool designed to allow unprivileged users to run commands as privileged users according predefined policies. The current version of pkexec doesn't handle the calling parameters count correctly and ends trying to execute environment variables as commands. An attacker can leverage this by crafting environment variables in such a way it'll induce pkexec to execute arbitrary code. When successfully executed the attack can cause a local privilege escalation given unprivileged users administrative rights on the target machine.

Description from the National Vulnerability Database.

What to do

CISA: Apply updates per vendor instructions.

Check whether you run Red Hat Polkit, then apply the vendor’s fix or mitigation from the advisories below. Because this flaw is exploited or has public exploit code, treat it as urgent and check for signs of compromise, not just the patch level.

Advisories and fixes

ThreatRoundup coverage

Sources: NVD, FIRST EPSS, CISA KEV, and public exploit databases (availability only). ThreatRoundup reports whether public exploit code exists but never links to it: fake proof-of-concepts that infect security researchers are common. This page updates automatically.