Local Privilege Escalation Vulnerability in polkit's pkexec Utility
CVE-2021-4034

7.8HIGH

Key Information:

Status
Vendor
CVE Published:
28 January 2022

Badges

👾 Exploit Exists🟡 Public PoC🟣 EPSS 88%🦅 CISA Reported

What is CVE-2021-4034?

A local privilege escalation vulnerability exists within the pkexec utility of polkit, a setuid tool that allows unprivileged users to execute commands as privileged users based on predetermined policies. Due to insufficient handling of the calling parameters, pkexec can misinterpret environment variables as executable commands. An attacker could exploit this flaw by carefully crafting environment variables, leading to the execution of arbitrary code. If successfully executed, this breach would grant unprivileged users administrative rights on the target machine, significantly compromising system integrity.

CISA has reported CVE-2021-4034

CISA provides regional cyber and physical services to support security and resilience across the United States. CISA monitor the most dangerious vulnerabilities and have identifed CVE-2021-4034 as being exploited but is not known by the CISA to be used in ransomware campaigns. This is subject to change at pace

The CISA's recommendation is: Apply updates per vendor instructions.

Affected Version(s)

polkit all

Exploit Proof of Concept (PoC)

PoC code is written by security researchers to demonstrate the vulnerability can be exploited. PoC code is also a key component for weaponization which could lead to ransomware.

References

EPSS Score

88% chance of being exploited in the next 30 days.

CVSS V3.1

Score:
7.8
Severity:
HIGH
Confidentiality:
High
Integrity:
High
Availability:
High
Attack Vector:
Local
Attack Complexity:
Low
Privileges Required:
Low
User Interaction:
None
Scope:
Unchanged

Timeline

  • 🟡

    Public PoC available

  • 👾

    Exploit known to exist

  • 🦅

    CISA Reported

  • Vulnerability published

  • Vulnerability Reserved

.