CVE-2022-42402 in PDF-XChange Editor
Summary
by MITRE • 01/26/2023
This vulnerability allows remote attackers to execute arbitrary code on affected installations of PDF-XChange Editor. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file. The specific flaw exists within the parsing of PDF files. Crafted data in an embedded U3D object can trigger a read past the end of an allocated buffer. An attacker can leverage this vulnerability to execute code in the context of the current process. Was ZDI-CAN-18632.
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Analysis
by VulDB Data Team • 04/29/2025
This vulnerability in PDF-XChange Editor represents a critical buffer overread flaw that enables remote code execution through malicious PDF files. The issue stems from improper handling of U3D objects within PDF documents, specifically when the software attempts to parse embedded 3D content. The vulnerability exists in the memory management routines responsible for processing these complex multimedia elements, where the application fails to properly validate the boundaries of allocated memory buffers. This allows an attacker to craft malicious PDF files containing specially formatted U3D objects that cause the parser to read beyond the intended memory allocation, potentially accessing sensitive data or executable code segments. The flaw is categorized under CWE-125 as an out-of-bounds read condition that can lead to information disclosure or arbitrary code execution. The attack requires user interaction through either visiting a malicious webpage hosting the compromised PDF or opening the malicious file directly, making it a typical client-side exploit vector that aligns with ATT&CK technique T1203 for legitimate program exploitation.
The technical implementation of this vulnerability demonstrates a classic buffer overflow pattern where the U3D object parsing code does not adequately validate the size or structure of incoming data before attempting to access memory locations. When the PDF parser encounters an embedded U3D object, it allocates memory based on initial size parameters contained within the object header, but fails to verify that subsequent data access operations remain within these boundaries. This allows an attacker to manipulate the U3D object structure to cause a read past the end of the allocated buffer, potentially corrupting memory or exposing memory addresses that can be leveraged for further exploitation. The impact extends beyond simple information disclosure as the memory corruption can be manipulated to redirect execution flow, enabling attackers to execute arbitrary code with the privileges of the PDF-XChange Editor process. This represents a significant risk since the editor typically runs with elevated privileges when processing documents, providing attackers with potential access to system resources and user data.
The operational impact of this vulnerability extends across multiple attack scenarios and threat vectors that align with modern cybersecurity threat models. Organizations relying on PDF-XChange Editor for document processing become vulnerable to targeted attacks where adversaries craft malicious PDF files designed to exploit this specific memory handling flaw. The requirement for user interaction creates a realistic attack surface that can be exploited through phishing campaigns, malicious websites, or social engineering tactics. Security teams must consider the implications of this vulnerability across enterprise environments where PDF processing is common, as it can serve as a foothold for broader compromise. The vulnerability's classification as a remote code execution flaw means that attackers can potentially establish persistent access without requiring physical presence or direct system compromise. This makes it particularly dangerous in enterprise environments where multiple users may process untrusted PDF documents regularly.
Mitigation strategies for this vulnerability should focus on both immediate protective measures and long-term architectural improvements. The most effective immediate response involves applying the vendor-provided security patches or updates that address the specific buffer overread condition in the U3D object parsing code. Organizations should also implement strict file validation policies that prevent processing of PDF files from untrusted sources, including implementing sandboxing mechanisms for PDF document handling. Network-level defenses can include web application firewalls that detect and block suspicious PDF content or content inspection tools that can identify malformed U3D objects. Security monitoring should be enhanced to detect unusual memory access patterns or process behavior that might indicate exploitation attempts. Additionally, user education and awareness programs should emphasize the dangers of opening untrusted PDF files, particularly those received through email or downloaded from unknown sources. Organizations should also consider implementing application whitelisting policies that restrict execution of PDF-XChange Editor only in controlled environments where the risk of malicious content is minimized. The vulnerability serves as a reminder of the importance of regular security updates and proper input validation in complex multimedia processing applications.