CVE-2021-36084 : Exploit Details and Defense Strategies

The CIL compiler in SELinux 3.2 has a use-after-free vulnerability, leading to a potential security risk. Here's what you need to know about CVE-2021-36084.

Understanding CVE-2021-36084

This section delves into the details of the CVE-2021-36084 vulnerability.

What is CVE-2021-36084?

The CVE-2021-36084 vulnerability involves a use-after-free issue in the CIL compiler within SELinux 3.2. Specifically, the vulnerability exists in __cil_verify_classperms, which is called from __cil_verify_classpermission and __cil_pre_verify_helper functions.

The Impact of CVE-2021-36084

This vulnerability could be exploited by an attacker to execute arbitrary code or cause a denial of service (DoS) condition, posing a serious security threat to systems running affected versions of SELinux.

Technical Details of CVE-2021-36084

Let's explore the technical aspects of CVE-2021-36084 for a better understanding of its implications.

Vulnerability Description

The use-after-free vulnerability in the CIL compiler allows an attacker to manipulate memory and potentially execute malicious code on the target system.

Affected Systems and Versions

SELinux 3.2 is affected by this vulnerability. Users and administrators of systems running this version should take immediate action to mitigate the risk.

Exploitation Mechanism

Malicious actors can exploit this vulnerability by crafting a special request to trigger the use-after-free condition, leading to unauthorized access or system compromise.

Mitigation and Prevention

To safeguard your systems from CVE-2021-36084, follow the mitigation steps outlined below.

Immediate Steps to Take

Update SELinux to a patched version provided by the vendor.
Monitor security advisories for any related updates or patches.

Long-Term Security Practices

Implement regular security updates and patches to prevent known vulnerabilities.
Conduct security audits and assessments to identify and address potential security gaps.

Patching and Updates

Stay informed about security announcements and updates from SELinux and related vendors to apply patches promptly and enhance system security.