CVE-2021-42380 : What You Need to Know

A detailed description of a use-after-free vulnerability in Busybox's awk applet, leading to denial of service and potential code execution.

Understanding CVE-2021-42380

What is CVE-2021-42380?

A use-after-free vulnerability in Busybox's awk applet can result in denial of service and potential execution of arbitrary code when parsing a malicious awk pattern in the clrvar function.

The Impact of CVE-2021-42380

This vulnerability can allow attackers to crash the application or potentially execute arbitrary code by crafting a specific awk pattern.

Technical Details of CVE-2021-42380

Vulnerability Description

The vulnerability arises from a use-after-free scenario encountered when processing certain awk patterns within the clrvar function of Busybox. This flaw can lead to denial of service and may enable attackers to execute malicious code.

Affected Systems and Versions

Vendor: Busybox
Product: Busybox
Affected Version: unspecified to less than 1.34.0
Version Type: Custom

Exploitation Mechanism

The vulnerability can be exploited by an attacker who crafts a specific malicious awk pattern, leading to the triggering of the use-after-free condition and potential code execution.

Mitigation and Prevention

Immediate Steps to Take

Update Busybox to version 1.34.0 or higher to mitigate this vulnerability.
Implement network segmentation to limit the impact of potential attacks.

Long-Term Security Practices

Regularly update software and apply security patches promptly.
Conduct regular security assessments and audits to identify and mitigate vulnerabilities.

Patching and Updates

Patch and update Busybox to version 1.34.0 or above to address the use-after-free vulnerability and enhance system security.