CVE-2019-12153 in PDFreactor
Summary
by MITRE
Lack of validation in the HTML parser in RealObjects PDFreactor before 10.1.10722 leads to SSRF, allowing attackers to access network or file resources on behalf of the server by supplying malicious HTML content.
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Analysis
by VulDB Data Team • 06/22/2020
The vulnerability identified as CVE-2019-12153 resides within the HTML parser component of RealObjects PDFreactor software versions prior to 10.1.10722. This issue represents a critical security flaw that fundamentally undermines the application's ability to process untrusted HTML content safely. The vulnerability stems from insufficient input validation mechanisms within the parser's handling of HTML documents, creating an avenue for malicious actors to exploit the system's trust model and gain unauthorized access to internal resources.
The technical flaw manifests when the PDFreactor application processes HTML content that contains crafted malicious elements designed to bypass normal validation checks. Specifically, the vulnerability enables server-side request forgery attacks where an attacker can manipulate the HTML parser to make requests to internal network services or access local file system resources. This occurs because the parser fails to properly sanitize or validate URLs and resource references embedded within the HTML content, allowing them to resolve to internal addresses that would normally be protected from external access. The vulnerability operates at the parsing layer, meaning it affects the initial processing phase before any content sanitization or security checks are applied.
The operational impact of this vulnerability is severe and multifaceted, as it allows attackers to potentially access sensitive internal network resources, file systems, and services that should remain isolated from external access. An attacker could leverage this vulnerability to enumerate internal network topology, access confidential files stored on the server, or even escalate their privileges by accessing system resources or configuration files. The implications extend beyond simple information disclosure, as the vulnerability could enable further exploitation chains leading to complete system compromise. This type of vulnerability directly violates the principle of least privilege and can result in significant data breaches or service disruption.
Security mitigation strategies for CVE-2019-12153 should prioritize immediate patching of affected PDFreactor installations to version 10.1.10722 or later, which contains the necessary validation fixes. Organizations should also implement network segmentation and firewall rules to restrict access to internal services from the PDFreactor server, reducing the potential impact of successful exploitation. Input sanitization measures should be enhanced to validate all HTML content before processing, with particular attention to URL schemes and resource references. The vulnerability aligns with CWE-918, which addresses server-side request forgery, and maps to ATT&CK technique T1190 for exploitation of remote services, highlighting the need for comprehensive network security controls and regular vulnerability assessments.
The broader implications of this vulnerability underscore the critical importance of proper input validation in security-critical applications, particularly those handling user-supplied content. This flaw demonstrates how seemingly innocuous parsing operations can become attack vectors when proper security controls are absent, emphasizing the need for defense-in-depth strategies and regular security auditing of all components within application stacks. Organizations processing HTML content should implement robust validation frameworks and maintain up-to-date security patches to prevent similar vulnerabilities from compromising their systems.