CVE-2021-4034
Polkit Project Polkit
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.
Exploitation status
- CISA has confirmed this is being exploited in the wild. That is an observation of real attacks, not a prediction.
- It is known to have been used in ransomware campaigns.
- US federal civilian agencies are required to remediate it by 2022-07-18. That deadline does not bind private companies, but it is a reasonable benchmark for how urgently CISA views it.
- A vendor advisory or patch reference has been published.
Required action
Apply updates per vendor instructions.
CISA’s wording, unedited.
What the metrics mean
- It is requires local access to the machine.
- For an attacker who can reach it, no special conditions are needed to exploit it.
- To exploit it, an ordinary user account is needed.
- Beyond that, no action by a user is required.
Scoring
- CVSS
- 7.8 (v3.1)
- Vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H- Weakness
- CWE-787
- Assigned by
- secalert@redhat.com
Dates
- Published
- 2022-01-28
- Last modified
- 2026-08-15
- Added to KEV
- 2022-06-27
- Remediation due
- 2022-07-18
- Sources
- CISA KEV, NVD
Affected products
- Polkit Project Polkit- 121
- Redhat Enterprise Linux Server Update Services For Sap Solutions7.6, 7.7, 8.1, 8.2, 8.4
- Redhat Enterprise Linux8.0
- Redhat Enterprise Linux Desktop7.0
- Redhat Enterprise Linux Eus8.2
- Redhat Enterprise Linux For Ibm Z Systems7.0, 8.0
- Redhat Enterprise Linux For Ibm Z Systems Eus8.2, 8.4
- Redhat Enterprise Linux For Power Big Endian7.0
- Redhat Enterprise Linux For Power Little Endian7.0, 8.0
- Redhat Enterprise Linux For Power Little Endian Eus8.1, 8.2, 8.4
- Redhat Enterprise Linux For Scientific Computing7.0
- Redhat Enterprise Linux Server6.0, 7.0
As listed in the NVD configuration data. Not a statement about your estate.
References
- 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
- https://www.qualys.com/2022/01/25/cve-2021-4034/pwnkit.txt
- 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