CVE-2021-42373 : Security Advisory and Response

A NULL pointer dereference in Busybox's man applet leads to denial of service when a section name is supplied but no page argument is given.

Understanding CVE-2021-42373

This CVE describes a vulnerability in Busybox's man applet that can result in a denial of service when specific input is provided.

What is CVE-2021-42373?

CVE-2021-42373 is a NULL pointer dereference vulnerability in Busybox's man applet that can be exploited to cause a denial of service (DoS) condition.

The Impact of CVE-2021-42373

The vulnerability can be exploited by supplying a section name without a page argument, leading to a crash of the man application, potentially disrupting system functionality.

Technical Details of CVE-2021-42373

This section provides technical details and specific information about the vulnerability.

Vulnerability Description

The vulnerability lies in Busybox's man applet code, where a NULL pointer dereference occurs when a section name is provided without a corresponding page argument.

Affected Systems and Versions

Vendor: Busybox
Product: Busybox
Affected Versions: All versions less than 1.34.0
Version Type: Custom

Exploitation Mechanism

An attacker supplies a section name without a page argument to the man application in Busybox
This triggers a NULL pointer dereference, leading to a DoS condition

Mitigation and Prevention

Steps to mitigate and prevent exploitation of CVE-2021-42373.

Immediate Steps to Take

Update Busybox to version 1.34.0 or newer to mitigate the vulnerability
Monitor system logs for any signs of exploitation or crashes related to the man applet

Long-Term Security Practices

Regularly update software and apply patches promptly to address known vulnerabilities
Implement robust input validation mechanisms in applications to prevent NULL pointer dereference issues

Patching and Updates

Apply the latest patches and updates provided by Busybox to ensure the system is protected against CVE-2021-42373