CVE-2021-42381 Explained : Impact and Mitigation

CVE-2021-42381 is a use-after-free vulnerability in Busybox's awk applet, leading to denial of service and potential code execution with a crafted awk pattern in the hash_init function.

Understanding CVE-2021-42381

What is CVE-2021-42381?

The CVE-2021-42381 vulnerability involves a use-after-free issue in Busybox's awk applet, where processing a malicious awk pattern in the hash_init function can result in denial of service and potentially allow an attacker to execute arbitrary code.

The Impact of CVE-2021-42381

Exploitation of this vulnerability can lead to denial of service conditions and, in more severe cases, unauthorized code execution on systems running affected versions of Busybox.

Technical Details of CVE-2021-42381

Vulnerability Description

A use-after-free vulnerability in Busybox's awk applet
Occurs when processing a crafted awk pattern in the hash_init function

Affected Systems and Versions

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

Exploitation Mechanism

Crafting a specific malicious awk pattern
Leveraging the hash_init function in Busybox's awk applet

Mitigation and Prevention

Immediate Steps to Take

Apply vendor patches or updates to mitigate the vulnerability
Implement network-level security controls to restrict access

Long-Term Security Practices

Regularly update and patch software and systems
Conduct security assessments and audits to detect vulnerabilities early

Patching and Updates

Update Busybox to version 1.34.0 or newer to address the use-after-free vulnerability