CVE-2023-23926 Explained : Impact and Mitigation

This CVE-2023-23926 involves an XML External Entity (XXE) vulnerability found in the APOC (Awesome Procedures on Cypher) core plugin, which is an add-on library for the Neo4j graph database. The vulnerability exists in the apoc.import.graphml procedure of the APOC core plugin prior to version 5.5.0 and 4.4.0.14 (4.4 branch) in the Neo4j graph database.

Understanding CVE-2023-23926

This section provides insights into what CVE-2023-23926 entails, its impact, technical details, and mitigation steps.

What is CVE-2023-23926?

The CVE-2023-23926 vulnerability is categorized as an XXE vulnerability, specifically related to the improper handling of XML external entities in the apoc.import.graphml procedure. This vulnerability potentially allows malicious actors to read local files, send HTTP requests, and conduct denial-of-service attacks on the application.

The Impact of CVE-2023-23926

The exploitation of this vulnerability could enable threat actors to remotely access local files, although restricted to one-line files based on the level of privileges. With the permission to write to the database, malicious entities could read any file, thereby compromising sensitive data. Moreover, improper XML formatting could lead to server crashes during local testing.

Technical Details of CVE-2023-23926

This section delves into the specific technical aspects of the CVE-2023-23926 vulnerability, including its description, affected systems, and exploitation mechanism.

Vulnerability Description

The vulnerability in the apoc.import.graphml procedure allows for XML External Entity (XXE) injection, where the XML parser permits external entities to be resolved insecurely. This provides an avenue for unauthorized access to local files, HTTP requests, and potential denial-of-service attacks.

Affected Systems and Versions

The APOC core plugin versions prior to 5.5.0 and 4.4.0.14 (4.4 branch) of the Neo4j graph database are impacted by this vulnerability. Specifically, versions below 4.4.0.14 are susceptible to exploitation.

Exploitation Mechanism

Exploiting this vulnerability involves manipulating the XML parser used by the apoc.import.graphml procedure to resolve external entities insecurely. By leveraging this flaw, attackers can perform unauthorized actions such as reading local files and initiating denial-of-service attacks.

Mitigation and Prevention

In light of the CVE-2023-23926 vulnerability, taking immediate steps, implementing long-term security practices, and ensuring timely patching and updates are crucial to mitigating risks and enhancing resilience against potential threats.

Immediate Steps to Take

It is recommended to upgrade to the patched versions (5.5.0 and above) to mitigate the XXE vulnerability. For those unable to upgrade immediately, controlling the allowlist of procedures accessible in the system can help mitigate the risk.

Long-Term Security Practices

Establishing secure coding practices, implementing input validation mechanisms, and conducting regular security assessments can bolster the overall security posture of applications and mitigate the risk of XXE vulnerabilities.

Patching and Updates

Regularly monitoring vendor advisories, applying security patches promptly, and staying informed about the latest security developments in libraries and plugins are essential practices to safeguard systems against known vulnerabilities like CVE-2023-23926.