CVE-2021-28840 : What You Need to Know

A Null Pointer Dereference vulnerability has been identified in various D-Link router models, which could be exploited by handling specific HTTP GET requests. This could lead to a NULL pointer dereference vulnerability in the upload_config function.

Understanding CVE-2021-28840

This section provides insights into the critical aspects of the CVE-2021-28840 vulnerability.

What is CVE-2021-28840?

The Null Pointer Dereference vulnerability in D-Link routers occurs in the upload_config function of the sbin/httpd binary. When the content in the upload_file variable is NULL during the handling of specific HTTP GET requests, the vulnerability is triggered through the strncasecmp function.

The Impact of CVE-2021-28840

Exploiting this vulnerability could result in a NULL pointer dereference situation, potentially leading to a denial of service (DoS) condition or arbitrary code execution on the affected device.

Technical Details of CVE-2021-28840

In this section, we delve into the technical specifics of CVE-2021-28840.

Vulnerability Description

The vulnerability allows malicious actors to exploit the NULL pointer dereference issue in D-Link routers, which could have severe consequences for the affected devices.

Affected Systems and Versions

D-Link DAP-2310 2.07.RC031, DAP-2330 1.07.RC028, DAP-2360 2.07.RC043, DAP-2553 3.06.RC027, DAP-2660 1.13.RC074, DAP-2690 3.16.RC100, DAP-2695 1.17.RC063, DAP-3320 1.01.RC014, and DAP-3662 1.01.RC022 are confirmed to be affected by this vulnerability.

Exploitation Mechanism

By manipulating HTTP GET requests sent to the routers, threat actors can trigger the NULL pointer dereference condition and potentially exploit the vulnerability.

Mitigation and Prevention

Protecting systems from CVE-2021-28840 requires immediate action and a long-term security strategy.

Immediate Steps to Take

It is crucial to monitor official D-Link communications and security bulletins, apply patches promptly, and consider network segmentation and access controls.

Long-Term Security Practices

Implementing secure coding practices, conducting regular security assessments, and keeping systems up to date are essential for long-term protection against such vulnerabilities.

Patching and Updates

Ensure that all affected D-Link routers are updated with the latest firmware and security patches to mitigate the risks associated with CVE-2021-28840.