CVE-2024-8843 in PDF-XChange
Summary
by MITRE • 11/23/2024
PDF-XChange Editor JB2 File Parsing Out-Of-Bounds Read Information Disclosure Vulnerability. This vulnerability allows remote attackers to disclose sensitive information 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 JB2 files. The issue results from the lack of proper validation of user-supplied data, which can result in a read past the end of an allocated object. An attacker can leverage this in conjunction with other vulnerabilities to execute arbitrary code in the context of the current process. Was ZDI-CAN-24495.
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Analysis
by VulDB Data Team • 03/09/2025
The CVE-2024-8843 vulnerability represents a critical out-of-bounds read flaw in PDF-XChange Editor's handling of JB2 image files, classified under CWE-125 as an "Out-of-bounds Read" condition. This vulnerability specifically affects the software's ability to process JB2 files, which are used for image compression within PDF documents. The flaw occurs during the parsing phase when the application fails to properly validate the boundaries of user-supplied data, leading to memory access beyond allocated buffer limits. This type of vulnerability falls under the broader category of memory safety issues that have been extensively documented in the cybersecurity community and are often exploited in advanced persistent threat campaigns.
The technical implementation of this vulnerability stems from insufficient input validation mechanisms within the JB2 file parser component of PDF-XChange Editor. When processing maliciously crafted JB2 files, the application attempts to read memory locations beyond the intended data boundaries, potentially exposing sensitive information stored in adjacent memory regions. This information disclosure can include stack contents, heap data, or other process memory that may contain authentication tokens, encryption keys, or other confidential data. The vulnerability requires user interaction to be exploited, meaning that a victim must either visit a malicious webpage containing embedded JB2 content or open a specially crafted file, making it a client-side attack vector that aligns with ATT&CK technique T1203 for "Exploitation for Client Execution."
The operational impact of this vulnerability extends beyond simple information disclosure, as it creates potential pathways for more severe exploits when combined with other vulnerabilities present in the system. An attacker who successfully leverages this out-of-bounds read could potentially use the leaked memory information to perform more sophisticated attacks such as stack pivoting, heap spraying, or information leakage that could aid in bypassing security mitigations like ASLR and DEP. The vulnerability's classification as a remote attack vector means that exploitation can occur without physical access to the target system, making it particularly dangerous in enterprise environments where users may encounter malicious content through web browsing or document attachments. This vulnerability demonstrates the importance of proper input validation and memory safety practices in software development, particularly in applications that process untrusted binary data formats.
Organizations affected by this vulnerability should implement immediate mitigations including updating to the latest version of PDF-XChange Editor where the flaw has been patched, implementing network-based protections such as web application firewalls to block suspicious JB2 file content, and establishing user education programs to avoid visiting untrusted websites or opening suspicious documents. The vulnerability also highlights the necessity of regular security assessments of third-party software components, as this type of flaw often goes undetected until it is actively exploited in the wild. Security teams should monitor threat intelligence feeds for indicators of compromise related to this vulnerability and consider implementing memory protection mechanisms such as stack canaries, address space layout randomization, and data execution prevention to reduce the exploitability of similar vulnerabilities in the future.