CVE-2023-0871 in Horizon
Summary
by MITRE • 08/11/2023
XXE injection in /rtc/post/ endpoint in OpenMNS Horizon 31.0.8 and versions earlier than 32.0.2 on multiple platforms is vulnerable to XML external entity (XXE) injection, which can be used for instance to force Horizon to make arbitrary HTTP requests to internal and external services. The solution is to upgrade to Meridian 2023.1.6, 2022.1.19, 2021.1.30, 2020.1.38 or Horizon 32.0.2 or newer. Meridian and Horizon installation instructions state that they are intended for installation within an organization's private networks and should not be directly accessible from the Internet.
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Analysis
by VulDB Data Team • 09/08/2023
The vulnerability identified as CVE-2023-0871 represents a critical XML external entity injection flaw within the OpenMNS Horizon platform, specifically affecting versions prior to 32.0.2. This vulnerability resides in the /rtc/post/ endpoint and demonstrates a fundamental weakness in how the system processes XML input, creating an attack surface that can be exploited to execute arbitrary HTTP requests against internal and external services. The flaw stems from insufficient input validation and sanitization of XML data, allowing malicious actors to manipulate the XML parser behavior through crafted external entity declarations. The vulnerability is particularly concerning as it enables attackers to leverage the application's network access capabilities to probe internal systems, potentially leading to lateral movement and information disclosure.
The technical implementation of this XXE vulnerability follows the classic pattern described in CWE-611, where external entity references are improperly handled during XML parsing operations. Attackers can construct malicious XML payloads that reference external entities, which when processed by the vulnerable Horizon application, can trigger outbound network requests to attacker-controlled servers or internal network resources. This behavior aligns with ATT&CK technique T1133, where adversaries use external proxies or network-based attacks to access internal resources. The vulnerability's exploitation potential extends beyond simple data exfiltration, as it can be used to perform service discovery, port scanning, and potentially establish command and control channels through the application's network connectivity. The attack vector is particularly dangerous because it requires minimal privileges and can be executed through standard HTTP POST requests to the affected endpoint.
The operational impact of CVE-2023-0871 is significant for organizations running vulnerable versions of OpenMNS Horizon, as it creates a persistent threat vector that can be exploited from outside the organization's perimeter. The vulnerability essentially allows attackers to use the legitimate application functionality as a proxy for network reconnaissance and exploitation activities. Organizations may experience unauthorized access to internal services, potential data leakage through outbound connections, and increased risk of further compromise through lateral movement. The vulnerability's exploitation can result in cascading security incidents, particularly when the affected system has access to sensitive internal resources or databases. Additionally, the attack can be used to bypass network segmentation controls, as the application's legitimate network access can be leveraged for malicious purposes.
The recommended mitigation strategy involves upgrading to the specified patched versions of Meridian and Horizon platforms, with Meridian versions 2023.1.6, 2022.1.19, 2021.1.30, and 2020.1.38, or Horizon version 32.0.2 and newer. This upgrade process should be conducted with proper change management procedures and thorough testing to ensure compatibility with existing configurations. Organizations should also implement network segmentation controls to restrict direct internet access to these applications, as noted in the vendor's installation instructions, which aligns with security best practices for protecting critical infrastructure components. Additional mitigations include implementing XML parser configurations that disable external entity processing, deploying web application firewalls to filter malicious XML content, and conducting regular security assessments to identify similar vulnerabilities in other components of the application stack. The vendor's guidance emphasizes that these applications are designed for private network deployment, making proper network architecture and access controls essential for maintaining security posture.