CVE-2021-23239 : Exploit Details and Defense Strategies

A vulnerability with CVE ID CVE-2021-23239 was published on January 12, 2021, by MITRE. It affects the sudoedit personality of Sudo versions prior to 1.9.5, potentially allowing a local unprivileged user to perform arbitrary directory-existence tests through a race condition.

Understanding CVE-2021-23239

This section will provide insights into the nature of the CVE-2021-23239 vulnerability.

What is CVE-2021-23239?

The vulnerability lies in the sudoedit component of Sudo versions earlier than 1.9.5, enabling an unprivileged local user to execute arbitrary directory-existence tests.

The Impact of CVE-2021-23239

If exploited, this vulnerability could allow a malicious local user to manipulate directories through symlinks, potentially leading to unauthorized data access or system compromise.

Technical Details of CVE-2021-23239

Delve into the technical aspects of the CVE-2021-23239 vulnerability.

Vulnerability Description

The flaw in the sudoedit component of Sudo before 1.9.5 permits a local unprivileged user to conduct directory-existence tests by exploiting a race condition in replacing a user-controlled directory with a symlink to a different path.

Affected Systems and Versions

All versions of Sudo preceding 1.9.5 are affected by this vulnerability.

Exploitation Mechanism

By exploiting the sudo_edit.c race condition, a local unprivileged user can replace a user-managed directory with a symbolic link to an arbitrary path, facilitating unauthorized directory manipulation.

Mitigation and Prevention

Learn about the strategies to mitigate and prevent the exploitation of CVE-2021-23239.

Immediate Steps to Take

Ensure timely patching and update of Sudo to version 1.9.5 or later to address the vulnerability and eliminate the risk of exploitation.

Long-Term Security Practices

Implement strict directory permission policies, conduct regular security audits, and stay informed about security advisories to bolster your system's defenses against similar vulnerabilities.

Patching and Updates

Frequently check for software updates and security advisories related to Sudo to promptly apply patches and reinforce system security against potential threats.