CVE-2021-4034
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.
At a glance
- Exploitability
- Can be exploited locally on the machine with a low-privilege account. High risk of data exposure, data tampering, service disruption.
- In the wild
- CISA lists this as exploited in real attacks. Treat as urgent.
- Fix
- A patch, advisory or fixed version is referenced. Upgrade or apply it.
Timeline
- ReservedThe CVE id was reserved by its CNA
- PublishedDisclosed publicly on CVE.org and NVD
- 2022-06-27 Exploited in the wildAdded to CISA's Known Exploited Vulnerabilities list
- 2022-07-18 Remediation deadlineCISA's due date for federal agencies to fix it
- Last updatedMost recent change to the record
Why it ranks here
- Exploited in the wild: yes, CISA lists it. This puts it above everything that is not.
- Exploit odds: 94.9% in the next 30 days (EPSS).
- Severity: 7.8 HIGH (CVSS).
- Fix: a patch or advisory is linked.
Details
- Published
- Last modified
- Added to CISA KEV
- 2022-06-27
- Exploit probability
- 94.9% · EPSS, next 30 days
- Weakness
- CWE-787 · Out-of-bounds write
- Record status
- Analyzed
Affected
- Polkit Project Polkit < 121
- Redhat Enterprise Linux Server Update Services For Sap Solutions 7.6
- Redhat Enterprise Linux Server Update Services For Sap Solutions 7.7
- Redhat Enterprise Linux 8.0
- Redhat Enterprise Linux Desktop 7.0
- Redhat Enterprise Linux Eus 8.2
- Redhat Enterprise Linux For IBM Z Systems 7.0
- Redhat Enterprise Linux For IBM Z Systems 8.0
Attack profile CVSS 3.1 · 7.8
- Attack vector
- Local
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Raw vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Is it in your code?
Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.
Read https://cve-list.com/agent/cve/CVE-2021-4034.md and follow it. Check whether this project is affected by CVE-2021-4034. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.
Fix and advisories
- https://access.redhat.com/security/vulnerabilities/RHSB-2022-001
- https://bugzilla.redhat.com/show_bug.cgi?id=2025869
- 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://access.redhat.com/security/vulnerabilities/RHSB-2022-001
- https://bugzilla.redhat.com/show_bug.cgi?id=2025869
- 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
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
- 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
- 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