CVE-2024-4327 in WebViewer
Summary
by MITRE • 04/30/2024
A vulnerability was found in Apryse WebViewer up to 10.8.0. It has been classified as problematic. This affects an unknown part of the component PDF Document Handler. The manipulation leads to cross site scripting. It is possible to initiate the attack remotely. The exploit has been disclosed to the public and may be used. Upgrading to version 10.9 is able to address this issue. It is recommended to upgrade the affected component. The associated identifier of this vulnerability is VDB-262419. NOTE: The vendor was contacted early about this disclosure and explains that the documentation recommends a strict Content Security Policy and the issue was fixed in release 10.9.
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Analysis
by VulDB Data Team • 04/02/2025
The Apryse WebViewer vulnerability represents a critical cross-site scripting flaw in the PDF Document Handler component that has been publicly disclosed and actively exploited. This security weakness affects versions up to 10.8.0 and allows remote attackers to inject malicious scripts into web pages viewed through the viewer. The vulnerability stems from inadequate input validation and output encoding within the PDF processing functionality, creating an attack surface where user-supplied content can be executed in the context of the victim's browser session. The flaw specifically impacts how the component handles PDF documents that contain malicious script code, potentially enabling attackers to execute arbitrary JavaScript commands on end-user systems.
The technical exploitation of this vulnerability follows standard XSS attack patterns where malicious input is embedded within PDF documents and rendered by the WebViewer component. When users open infected PDF files through the vulnerable viewer, the malicious scripts execute in the context of the viewer's domain, bypassing normal browser security restrictions. This allows attackers to perform actions such as stealing session cookies, redirecting users to malicious sites, or injecting additional malware into the victim's browsing environment. The remote attack vector means that no local system compromise is necessary, making this vulnerability particularly dangerous for organizations that process untrusted PDF content.
The operational impact of this vulnerability extends beyond simple script execution to encompass potential data breaches and system compromise. Organizations relying on Apryse WebViewer for document processing may face unauthorized access to sensitive information, especially in environments where users frequently handle external PDF documents. The vulnerability's classification as problematic indicates that it can be readily exploited without specialized knowledge, making it attractive to threat actors seeking automated attack vectors. Security teams must consider the potential for lateral movement within networks if attackers use this vulnerability to establish persistent access through compromised user sessions.
The recommended mitigation strategy involves upgrading to version 10.9 or later, which includes proper input sanitization and output encoding mechanisms that prevent script injection attacks. Organizations should also implement strict Content Security Policy headers as recommended by the vendor, though this serves as a supplementary defense rather than a complete solution. Security controls should include monitoring for suspicious PDF document handling activities and implementing additional sandboxing measures when processing untrusted content. The vulnerability's disclosure status means that defensive measures should be prioritized immediately, as the exploit is publicly available and actively used in threat campaigns.
This vulnerability aligns with CWE-79 Cross-site Scripting and follows ATT&CK techniques related to initial access through malicious documents and execution via web-based attacks. The fix implemented in version 10.9 demonstrates proper remediation through input validation and output encoding, addressing the root cause of the XSS vulnerability. Organizations should conduct thorough security assessments of their PDF processing workflows and implement comprehensive patch management procedures to prevent similar vulnerabilities from being exploited in other components of their document handling infrastructure.