CVE-2021-42383 : Security Advisory and Response

A detailed overview of CVE-2021-42383, a use-after-free vulnerability in Busybox that can lead to denial of service and potential code execution.

Understanding CVE-2021-42383

What is CVE-2021-42383?

CVE-2021-42383 is a use-after-free vulnerability found in Busybox's awk applet. Exploitation of this vulnerability can result in denial of service and potentially allow an attacker to execute arbitrary code when processing a specifically crafted awk pattern in the evaluate function.

The Impact of CVE-2021-42383

This vulnerability has the potential to cause denial of service and may lead to arbitrary code execution, posing a significant security risk to systems running affected versions of Busybox.

Technical Details of CVE-2021-42383

Vulnerability Description

The vulnerability arises due to improper handling of memory operations in Busybox's awk applet, specifically in the evaluate function, which can result in a use-after-free condition.

Affected Systems and Versions

Vendor: Busybox
Product: Busybox
Versions Affected: All versions less than 1.34.0

Exploitation Mechanism

The vulnerability can be exploited by supplying a carefully crafted awk pattern during the evaluation process, triggering the use-after-free condition and potentially leading to denial of service or code execution.

Mitigation and Prevention

Immediate Steps to Take

Update Busybox to version 1.34.0 or later to mitigate the vulnerability.
Monitor vendor security advisories for patch availability and apply fixes promptly.

Long-Term Security Practices

Regularly check for security updates and patches for all software components.
Follow secure coding practices to minimize the risk of memory-related vulnerabilities.

Patching and Updates

Apply patches and updates from software vendors as soon as they are available to address known vulnerabilities.