CVE-2021-42386 Explained : Impact and Mitigation

A detailed overview of CVE-2021-42386, including its impact, technical details, and mitigation steps.

Understanding CVE-2021-42386

What is CVE-2021-42386?

CVE-2021-42386 is a use-after-free vulnerability in Busybox's awk applet. This vulnerability can lead to denial of service and potentially code execution when processing a crafted awk pattern in the nvalloc function.

The Impact of CVE-2021-42386

This vulnerability can result in denial of service attacks and potential code execution, posing a significant risk to systems running affected versions of Busybox.

Technical Details of CVE-2021-42386

Vulnerability Description

The use-after-free in Busybox's awk applet allows attackers to manipulate the memory allocation process, leading to crashes or possible code execution.

Affected Systems and Versions

Vendor: Busybox
Product: Busybox
Affected Versions:
Version: Unspecified
Less Than: 1.34.0
Status: Affected
Version Type: Custom

Exploitation Mechanism

Attackers can exploit this vulnerability by providing a specially crafted awk pattern to the nvalloc function, triggering the use-after-free condition and potentially gaining unauthorized access or disrupting system operations.

Mitigation and Prevention

Immediate Steps to Take

Apply vendor patches or updates promptly to address the vulnerability.
Monitor security advisories from Busybox and other relevant sources for mitigation guidance.
Consider limiting access to vulnerable components or implementing network controls to reduce the attack surface.

Long-Term Security Practices

Conduct regular security assessments and penetration testing to identify and remediate vulnerabilities proactively.
Implement secure coding practices and perform code reviews to prevent similar memory-related issues.

Patching and Updates

It is crucial to apply the patch provided by Busybox to mitigate CVE-2021-42386 effectively and prevent potential exploitation of the vulnerability.