CVE-2023-23924 : Exploit Details and Defense Strategies

This CVE involves an URI validation failure on SVG parsing in Dompdf, a tool for converting HTML to PDF. The vulnerability can be exploited by passing

<image>

tags with uppercase letters, leading to arbitrary object unserialize on PHP < 8.

Understanding CVE-2023-23924

This section will provide an overview of CVE-2023-23924 and its implications.

What is CVE-2023-23924?

CVE-2023-23924 is a vulnerability in Dompdf 2.0.1 that allows for bypassing URI validation on SVG parsing through specific tag manipulation. Exploiting this vulnerability can result in arbitrary URL calls with arbitrary protocols, potentially leading to serious consequences on PHP versions prior to 8.0.0.

The Impact of CVE-2023-23924

The impact of this vulnerability can range from arbitrary file deletion to remote code execution, depending on the classes available in the system. Attackers could potentially exploit this flaw to execute malicious code and compromise the targeted system.

Technical Details of CVE-2023-23924

This section delves into the technical aspects of CVE-2023-23924, including the vulnerability description, affected systems, and exploitation mechanism.

Vulnerability Description

The vulnerability in Dompdf 2.0.1 allows for circumventing URI validation on SVG parsing by leveraging specific tag structures. This can enable attackers to trigger arbitrary object unserialize on PHP instances below version 8.0.0, potentially leading to serious security breaches.

Affected Systems and Versions

Dompdf versions prior to 2.0.2 are impacted by this vulnerability. Specifically, version 2.0.1 is susceptible to the URI validation failure during SVG parsing, potentially exposing systems to exploitation by threat actors.

Exploitation Mechanism

By manipulating

<image>

tags with uppercase letters within SVG files, attackers can exploit the vulnerability to bypass URI validation in Dompdf. This manipulation can pave the way for executing arbitrary URL calls with various protocols, posing a significant security risk.

Mitigation and Prevention

To address CVE-2023-23924 and mitigate its potential impact, immediate steps should be taken along with the adoption of long-term security practices and regular patching.

Immediate Steps to Take

Users of Dompdf are advised to update to version 2.0.2 or newer to mitigate the URI validation failure on SVG parsing. Additionally, implementing proper input validation and sanitization can help prevent similar exploits in the future.

Long-Term Security Practices

It is crucial for organizations to prioritize security awareness and education among developers to prevent similar vulnerabilities in the software development and deployment processes. Regular security assessments and code reviews can further enhance the overall security posture.

Patching and Updates

Staying vigilant for security updates from Dompdf and promptly applying patches to address known vulnerabilities is essential for maintaining a secure environment. Regularly updating software components can help safeguard against potential threats and ensure system integrity.