CVE-2019-16951 in Web Chat
Summary
by MITRE
A remote file include (RFI) issue was discovered in Enghouse Web Chat 6.2.284.34. One can replace the localhost attribute with one's own domain name. When the product calls this domain after the POST request is sent, it retrieves an attacker's data and displays it. Also worth mentioning is the amount of information sent in the request from this product to the attacker: it reveals information the public should not have. This includes pathnames and internal ip addresses.
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Analysis
by VulDB Data Team • 02/13/2024
The vulnerability identified as CVE-2019-16951 represents a critical remote file inclusion flaw within Enghouse Web Chat version 6.2.284.34 that exposes organizations to significant security risks. This issue stems from improper input validation and sanitization mechanisms within the application's handling of the localhost attribute parameter. The flaw allows remote attackers to manipulate the target system by substituting the localhost reference with an attacker-controlled domain name, creating a pathway for unauthorized code execution and data exfiltration. The vulnerability specifically manifests when the application processes POST requests and subsequently makes outbound connections to the attacker-controlled domain, enabling the retrieval and execution of malicious content from external sources.
The technical implementation of this vulnerability demonstrates a classic remote file inclusion attack vector where the application's trust in user-supplied input leads to arbitrary code execution. When the product makes HTTP requests to the attacker's domain following POST operations, it effectively acts as a proxy for malicious content delivery. The flaw operates at the application layer and leverages the application's inherent trust in its own configuration parameters, failing to validate or sanitize external references before processing them. This vulnerability directly maps to CWE-88, which describes improper neutralization of special elements used in an expression, and more specifically to CWE-94, which covers improper control of generation of code, both of which are fundamental to remote code execution vulnerabilities.
The operational impact of this vulnerability extends beyond simple code execution to include comprehensive information disclosure that exposes sensitive system internals. During the malicious request process, the application inadvertently reveals critical system information including internal pathnames and IP addresses that should remain confidential within the organization's network perimeter. This information disclosure aspect significantly amplifies the threat level as it provides attackers with detailed reconnaissance data that can be used for further exploitation attempts. The exposed internal network information creates opportunities for attackers to map network topologies, identify system configurations, and plan subsequent attacks against other components within the same network infrastructure. This vulnerability can be categorized under ATT&CK technique T1059.007 for Windows Command Shell and T1082 for System Information Discovery, demonstrating how the flaw enables both code execution and reconnaissance capabilities.
Organizations utilizing Enghouse Web Chat 6.2.284.34 face substantial risk from this vulnerability, particularly in environments where network segmentation and access controls are not properly implemented. The vulnerability can be exploited remotely without requiring authentication, making it particularly dangerous for publicly accessible systems. Attackers can leverage this flaw to establish persistent backdoors, exfiltrate sensitive data, or use the compromised system as a launching point for attacks against other network resources. The information disclosure component particularly threatens organizations with strict compliance requirements, as the exposure of internal system paths and IP addresses may violate data protection regulations and security standards. The vulnerability's exploitation requires minimal technical expertise, making it attractive to both sophisticated and less experienced threat actors. Mitigation strategies should include immediate patching of the affected software, implementation of network segmentation controls, and monitoring for suspicious outbound connections to external domains. Additionally, organizations should consider implementing web application firewalls and input validation controls to prevent similar vulnerabilities from occurring in other applications within their environment.