OpenCMS XXE Vulnerability Analysis (CVE-2023-42344 et al.)

OpenCMS XXE Vulnerability Summary Vulnerability Overview Vulnerability Name: XXE, You Can Depend On Me (OpenCMS CVE-2023-42344 and Friends) CVE Numbers: CVE-2023-42344, CVE-2023-42343, CVE-2023-42345, CVE-2023-42346 Vulnerability Type: XML External Entity Injection (XXE) Affected Component: The endpoint within the OpenCMS framework (based on the Apache Chemistry library). Trigger Mechanism: An attacker sends an XML-formatted POST request containing SQL-style syntax to the endpoint. The vulnerability is triggered by a flaw in the Apache Chemistry parser when processing external DTD files, leading to XXE. Impact Scope Affected Versions: OpenCMS 9.5.3 and earlier versions (as of the time of writing, approximately 1,000 instances are still running this version). Deployment Status: Although the latest version is 16.0, there are still approximately 6,000 instances running OpenCMS 7, which was released 15 years ago. Potential Risk: Attackers can exploit this vulnerability to read sensitive files on the server, such as files, configuration files, and hardcoded credentials, potentially leading to information disclosure or further attacks. Remediation Official Recommendation: Upgrade OpenCMS to the latest version (16.0 or higher). Temporary Mitigation Measures: Ensure that the endpoint is protected by strict authentication and access control. Note: Although there is a lockout mechanism even against brute-force attacks using Basic Auth, this does not apply to the endpoint itself. Avoid allowing the download of sensitive resources such as files in the configuration. Implement least-privilege configurations for the application resource repository to prevent unauthorized users from enumerating or manipulating objects via the "TCK" feature. POC / Exploit Code The article does not provide a complete, directly executable POC code block, but describes the exploitation method: > Send an XML-formatted POST request to the endpoint containing SQL-style syntax. For example, attempt to inject a simple XXE Out of Bounds (OOB) payload to trigger the parser to output an error stack trace, thereby confirming the vulnerability's presence. For the specific request structure, refer to the Apache Chemistry documentation: https://documentation.opencms.org/opencms-documentation/interfaces/cmis/index.html > Note: Actual exploitation requires constructing specific XML content; the article does not provide a complete payload example.

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OpenCMS XXE Vulnerability Analysis (CVE-2023-42344 et al.)