CVE-2023-6721 Explained : Impact and Mitigation

This CVE-2023-6721 was published by INCIBE on December 13, 2023, following its discovery on December 12, 2023. The vulnerability affects the product Repox, with versions up to and including 2.3.7 being vulnerable to exploitation.

Understanding CVE-2023-6721

This vulnerability involves an XEE (XML External Entity) issue in Repox, allowing a remote attacker to manipulate the application's XML data processing in the fileupload function. This manipulation can lead to unauthorized access to the server's file system.

What is CVE-2023-6721?

The CVE-2023-6721 vulnerability in Repox is categorized under CWE-611 - Improper Restriction of XML External Entity Reference. It stems from an XEE flaw that enables threat actors to interfere with the XML data processing, leading to potential server compromise.

The Impact of CVE-2023-6721

The impact of CVE-2023-6721 is rated as high severity with a CVSS base score of 8.3. This vulnerability can result in a breach of confidentiality, integrity, and availability of the affected system. The CAPEC-221 XML External Entities Blowup describes the potential exploit.

Technical Details of CVE-2023-6721

The vulnerability in Repox arises from an improper restriction in handling XML external entity references. Attackers can exploit this flaw remotely via a network connection with low attack complexity and privilege requirements.

Vulnerability Description

The XEE vulnerability in Repox allows attackers to interfere with the application's XML data processing, enabling unauthorized access to the server's file system through the fileupload function.

Affected Systems and Versions

Repox versions up to and including 2.3.7 are impacted by CVE-2023-6721 due to the XEE vulnerability present in the fileupload function of the application.

Exploitation Mechanism

Exploiting this vulnerability involves sending specially crafted XML data to the application, tricking it into processing these entities and providing unauthorized access to the server's file system.

Mitigation and Prevention

To mitigate the risks associated with CVE-2023-6721, immediate actions and long-term security practices must be implemented to protect systems from exploitation.

Immediate Steps to Take

Organizations using Repox should update to a patched version or apply vendor-provided workarounds to address the XEE vulnerability.
Implement network segmentation and access controls to limit exposure to potential attacks targeting XML data processing.

Long-Term Security Practices

Regularly monitor and audit XML data processing for unusual patterns or unauthorized access attempts.
Educate developers and system administrators on secure coding practices to prevent XEE vulnerabilities in applications.

Patching and Updates

As of the current information available, there is no reported solution for CVE-2023-6721. Organizations should stay informed through official channels for updates and patches released by the vendor to address the XEE vulnerability in Repox.