polkitproject polkit CVE-2021-4034 vulnerability in Polkitproject and Other Products
Published on January 28, 2022

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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.

NVD

Known Exploited Vulnerability

This Red Hat Polkit Out-of-Bounds Read and Write Vulnerability is part of CISA's list of Known Exploited Vulnerabilities. The Red Hat polkit pkexec utility contains an out-of-bounds read and write vulnerability which allows for privilege escalation with administrative rights.

The following remediation steps are recommended / required by July 18, 2022: Apply updates per vendor instructions.

Vulnerability Analysis

CVE-2021-4034 is exploitable with local system access, and requires small amount of user privileges. This vulnerability is considered to have a low attack complexity. This vulnerability is known to be actively exploited by threat actors. The potential impact of an exploit of this vulnerability is considered to be very high.

Attack Vector:
LOCAL
Attack Complexity:
LOW
Privileges Required:
LOW
User Interaction:
NONE
Scope:
UNCHANGED
Confidentiality Impact:
HIGH
Integrity Impact:
HIGH
Availability Impact:
HIGH

Weakness Type

What is a Memory Corruption Vulnerability?

The software writes data past the end, or before the beginning, of the intended buffer. Typically, this can result in corruption of data, a crash, or code execution. The software may modify an index or perform pointer arithmetic that references a memory location that is outside of the boundaries of the buffer. A subsequent write operation then produces undefined or unexpected results.

CVE-2021-4034 has been classified to as a Memory Corruption vulnerability or weakness.


Products Associated with CVE-2021-4034

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Exploit Probability

EPSS
87.26%
Percentile
99.44%

EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.