CVE-2021-28904 : Exploit Details and Defense Strategies

A detailed article outlining the CVE-2021-28904 vulnerability in the libyang library.

Understanding CVE-2021-28904

This section will cover the impact, technical details, and mitigation strategies related to CVE-2021-28904.

What is CVE-2021-28904?

The CVE-2021-28904 vulnerability exists in the libyang library, specifically in the function ext_get_plugin() up to version v1.0.225. It fails to validate the value of the revision parameter, leading to a potential crash when invoking strcmp(revision, ext_plugins[u].revision).

The Impact of CVE-2021-28904

Exploitation of this vulnerability could result in a denial-of-service condition or potentially allow an attacker to execute arbitrary code on the affected system, posing a severe security risk.

Technical Details of CVE-2021-28904

Let's delve into the specifics of the vulnerability.

Vulnerability Description

The flaw lies in the lack of validation for the revision parameter in the ext_get_plugin() function, which can be exploited to trigger a crash in the library.

Affected Systems and Versions

The vulnerability affects libyang versions up to v1.0.225, exposing systems that utilize these versions to the risk outlined above.

Exploitation Mechanism

By not verifying the revision value, an attacker can craft malicious input that triggers the strcmp() operation, leading to a crash or potentially enabling further exploitation.

Mitigation and Prevention

Learn how to mitigate the risks associated with CVE-2021-28904.

Immediate Steps to Take

Users are advised to update to a patched version of libyang that addresses the vulnerability. Additionally, exercise caution when processing untrusted input to prevent exploitation.

Long-Term Security Practices

Adopt a proactive security stance by regularly updating software, implementing secure coding practices, and conducting routine security assessments to detect and address vulnerabilities.

Patching and Updates

Stay informed about security updates for libyang and promptly apply patches to ensure that your systems are protected against known vulnerabilities.