CVE-2021-29296 Explained : Impact and Mitigation

A Null Pointer Dereference vulnerability in D-Link DIR-825 2.10b02 could allow a remote attacker to cause a denial of service. The issue arises when an HTTP request with URL /vct_wan is sent, triggering the vulnerability and resulting in a segmentation fault. Please note that the DIR-825 and all hardware revisions are considered End of Life, and this issue will not be patched.

Understanding CVE-2021-29296

This section delves into the details of the CVE-2021-29296 vulnerability affecting D-Link DIR-825 2.10b02.

What is CVE-2021-29296?

CVE-2021-29296 is a Null Pointer Dereference vulnerability in the D-Link DIR-825 2.10b02 router, exploitable via an HTTP request with URL /vct_wan, leading to a denial of service.

The Impact of CVE-2021-29296

The vulnerability can be exploited by a remote malicious user to cause a denial of service by triggering a segmentation fault in the sbin/httpd process of the affected router.

Technical Details of CVE-2021-29296

This section provides a more in-depth look at the technical aspects of CVE-2021-29296.

Vulnerability Description

The vulnerability occurs due to a Null Pointer Dereference when the strchr function is invoked with a NULL argument, leading to a segmentation fault.

Affected Systems and Versions

D-Link DIR-825 2.10b02 is the specific version affected by this vulnerability, impacting all hardware revisions of the router.

Exploitation Mechanism

Remote attackers can exploit this vulnerability by sending a crafted HTTP request with the specific URL /vct_wan, which triggers the issue, causing a denial of service.

Mitigation and Prevention

In this section, we discuss ways to mitigate and prevent the exploitation of CVE-2021-29296.

Immediate Steps to Take

Given that the affected hardware is End of Life and the issue will not be patched, users are advised to consider alternative router options to maintain security.

Long-Term Security Practices

To enhance overall security posture, organizations should regularly update their networking equipment and follow best practices to safeguard against similar vulnerabilities.

Patching and Updates

As the DIR-825 router series is no longer supported, implementing additional security measures and considering hardware upgrades are crucial to mitigate risks effectively.