CVE-2021-33516 Explained : Impact and Mitigation

An issue was discovered in GUPnP before 1.0.7 and 1.1.x and 1.2.x before 1.2.5, allowing DNS rebinding. A remote web server can exploit this vulnerability to trick a victim's browser into triggering actions against local UPnP services.

Understanding CVE-2021-33516

This CVE identifies a security issue in GUPnP versions before 1.0.7 and 1.1.x and 1.2.x before 1.2.5, enabling DNS rebinding.

What is CVE-2021-33516?

CVE-2021-33516 is a vulnerability in GUPnP that could be exploited by a remote web server to manipulate a victim's browser into affecting local UPnP services implemented via the library.

The Impact of CVE-2021-33516

This vulnerability poses a risk of data exfiltration, data tampering, and other potentially harmful actions based on the affected UPnP services.

Technical Details of CVE-2021-33516

The following details outline the vulnerability specifics:

Vulnerability Description

The issue in GUPnP allows for DNS rebinding, permitting unauthorized access to manipulate local UPnP services remotely.

Affected Systems and Versions

GUPnP versions prior to 1.0.7, 1.1.x, and 1.2.x before 1.2.5 are impacted by this vulnerability.

Exploitation Mechanism

Remote web servers can exploit this flaw to deceive users' browsers into triggering actions on local UPnP services.

Mitigation and Prevention

To address CVE-2021-33516 effectively, consider the following:

Immediate Steps to Take

Update GUPnP to versions 1.0.7, 1.1.x, or 1.2.5 to mitigate the risk of DNS rebinding.
Implement network segmentation to restrict access to vulnerable services.

Long-Term Security Practices

Regularly monitor for security advisories and updates related to GUPnP and apply patches promptly.
Conduct security assessments to identify and address any lingering vulnerabilities in the network.

Patching and Updates

Stay informed about new releases and security fixes from GUPnP and promptly install updates to protect against known vulnerabilities.