Critical Zero-Day Vulnerabilities in PDF Platforms Expose Millions to Cyber Threats
In a recent disclosure, Novee Security has identified 16 zero-day vulnerabilities within widely used PDF platforms, notably Apryse WebViewer (formerly PDFTron) and Foxit PDF cloud services. These vulnerabilities, encompassing critical flaws such as OS Command Injection, DOM-based Cross-Site Scripting (XSS), Server-Side Request Forgery (SSRF), and Path Traversal, pose significant risks to millions of enterprise users globally.
Understanding the Vulnerabilities
The identified vulnerabilities span multiple layers of the affected platforms:
1. User Interface Layer: The React-based UI iframe in Apryse WebViewer accepts untrusted inputs from various sources, including query strings, `postMessage`, remote JSON configurations, and URL fragments.
2. Document Engine Layer: This JavaScript/WebAssembly component handles the parsing and rendering of PDF documents.
3. Server-Side SDK Layer: Responsible for HTML-to-PDF conversion and thumbnail generation, this layer processes server-side operations.
Each of these layers represents a distinct trust boundary. The vulnerabilities primarily arise from inadequate validation of inputs crossing these boundaries, leading to potential exploitation.
Research Methodology
Novee Security employed a hybrid approach combining human expertise with artificial intelligence to uncover these vulnerabilities. Initially, human researchers identified foundational vulnerability patterns. These insights were then encoded into specialized AI agents:
– Tracer: Mapped sink enumeration and backward source-to-sink chains.
– Resolver: Analyzed control flow and validation boundaries.
– Bypass: Constructed proof-of-concept exploits to demonstrate vulnerability exploitability.
This systematic approach ensured comprehensive coverage of the platforms’ attack surfaces.
Key Vulnerabilities Highlighted
1. OS Command Injection in Foxit PDF SDK (CVSS 9.8): A critical flaw in the Node.js signature server of Foxit PDF SDK for Web allows unauthenticated attackers to execute arbitrary code. The `md` parameter from a POST request is directly concatenated into `process.execSync()` without proper sanitization, enabling remote code execution.
2. SSRF in Apryse WebViewer (CVE-2025-70400, High Severity): This vulnerability permits attackers to manipulate the server into fetching and rendering attacker-controlled content, potentially exposing internal network resources.
3. DOM-Based XSS in Apryse WebViewer (CVE-2025-70402, Critical Severity): By exploiting the `uiConfig` query parameter, attackers can inject malicious content that is processed without proper sanitization, leading to arbitrary code execution within the user’s browser.
4. Stored DOM XSS via PDF Annotations (CVE-2025-70401, High Severity): Malicious input in the PDF annotation author field can execute scripts during component re-rendering, posing persistent threats to users.
5. Path Traversal in Foxit Embedded Calculator (CVE-2025-66500, Medium Severity): The embedded calculator component’s `postMessage` handler improperly validates input, allowing attackers to traverse directories and potentially access unauthorized files.
Implications for Users and Organizations
The exploitation of these vulnerabilities can lead to severe consequences, including:
– Remote Code Execution: Attackers can gain control over affected systems, leading to data breaches, system manipulation, and deployment of malware.
– Data Exfiltration: Sensitive information can be accessed and extracted without authorization.
– Network Compromise: Internal networks can be exposed to external threats, increasing the risk of widespread attacks.
– Persistent XSS Attacks: Users can be subjected to ongoing malicious scripts, compromising their security and privacy.
Vendor Responses and Mitigation Measures
Upon responsible disclosure by Novee Security, both Apryse and Foxit have acknowledged the vulnerabilities and coordinated patches or mitigations:
– Apryse WebViewer: Users are advised to update to the latest version, which includes fixes for the identified vulnerabilities.
– Foxit PDF SDK: A patched version addressing the critical OS Command Injection vulnerability has been released. Users should apply this update promptly.
Recommendations for Users
To safeguard against potential exploits:
1. Update Software: Ensure that all PDF-related applications are updated to their latest versions to incorporate security patches.
2. Validate Inputs: Implement strict input validation to prevent malicious data from being processed.
3. Monitor Systems: Regularly review system logs and network traffic for unusual activities that may indicate exploitation attempts.
4. Educate Users: Train staff to recognize phishing attempts and avoid opening untrusted PDF files.
Conclusion
The discovery of these 16 zero-day vulnerabilities underscores the critical need for robust security practices in handling PDF documents. Organizations must remain vigilant, apply necessary updates, and adopt proactive measures to protect their systems and data from emerging cyber threats.
