CVE-2021-4034
Act now ● On CISA KEV — actively exploited used in ransomware
Actively exploited — on the CISA KEV list.
CVSS breakdown
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
| Attack Vector | L | Local |
| Attack Complexity | L | Low |
| Privileges Required | L | Low |
| User Interaction | N | None |
| Scope | U | Unchanged |
| Confidentiality | H | High |
| Integrity | H | High |
| Availability | H | High |
Timeline
- 2022-01-28 — Published (NVD)
- 2022-06-27 — Added to CISA KEV (actively exploited)
- 2022-07-18 — CISA patch-by deadline
- 2026-08-15 — Last modified (NVD)
Description
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.
Affected
References
- exploit http://packetstormsecurity.com/files/166196/Polkit-pkexec-Local-Privilege-Escalation.html
- http://packetstormsecurity.com/files/166200/Polkit-pkexec-Privilege-Escalation.html
- https://access.redhat.com/security/vulnerabilities/RHSB-2022-001
- https://bugzilla.redhat.com/show_bug.cgi?id=2025869
- https://cert-portal.siemens.com/productcert/pdf/ssa-330556.pdf
- https://gitlab.freedesktop.org/polkit/polkit/-/commit/a2bf5c9c83b6ae46cbd5c779d3055bff81ded683
- https://www.oracle.com/security-alerts/cpuapr2022.html
- exploit https://www.qualys.com/2022/01/25/cve-2021-4034/pwnkit.txt
- exploit https://www.secpod.com/blog/local-privilege-escalation-vulnerability-in-major-linux-distributions-cve-2021-4034/
- https://www.starwindsoftware.com/security/sw-20220818-0001/
- https://www.suse.com/support/kb/doc/?id=000020564
- exploit http://packetstormsecurity.com/files/166196/Polkit-pkexec-Local-Privilege-Escalation.html
- http://packetstormsecurity.com/files/166200/Polkit-pkexec-Privilege-Escalation.html
- https://access.redhat.com/security/vulnerabilities/RHSB-2022-001
- https://bugzilla.redhat.com/show_bug.cgi?id=2025869
- https://cert-portal.siemens.com/productcert/pdf/ssa-330556.pdf
- https://gitlab.freedesktop.org/polkit/polkit/-/commit/a2bf5c9c83b6ae46cbd5c779d3055bff81ded683
- https://www.oracle.com/security-alerts/cpuapr2022.html
- exploit https://www.qualys.com/2022/01/25/cve-2021-4034/pwnkit.txt
- exploit https://www.secpod.com/blog/local-privilege-escalation-vulnerability-in-major-linux-distributions-cve-2021-4034/
- https://www.starwindsoftware.com/security/sw-20220818-0001/
- https://www.suse.com/support/kb/doc/?id=000020564
- exploit https://www.vicarius.io/vsociety/posts/pwnkit-pkexec-lpe-cve-2021-4034
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-4034