CVE-2024-8823 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-24261.
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Analysis
by VulDB Data Team • 03/09/2025
The CVE-2024-8823 vulnerability represents a critical out-of-bounds read flaw within the PDF-XChange Editor software's handling of JB2 image files. This vulnerability falls under the category of information disclosure and code execution risks, as it allows remote attackers to extract sensitive data from memory locations beyond the intended bounds of allocated objects. The flaw specifically manifests during the parsing process of JB2 files, which are commonly used for image compression and storage within PDF documents. The vulnerability's classification aligns with CWE-125, which describes out-of-bounds read conditions where an application reads data beyond the boundaries of a buffer or allocated memory region. This type of vulnerability is particularly dangerous because it can expose sensitive information such as memory contents, system pointers, or cryptographic keys that may be stored in adjacent memory locations. The attack vector requires user interaction, meaning that victims must either visit a malicious webpage or open a specially crafted malicious file containing the vulnerable JB2 data structure. This requirement for user interaction reduces the severity of automatic exploitation but does not eliminate the risk entirely, as social engineering techniques can easily overcome this barrier. The vulnerability's impact extends beyond simple information disclosure, as the out-of-bounds read condition can be leveraged in combination with other vulnerabilities to achieve arbitrary code execution within the context of the current process, making it a significant threat to system security.
The technical implementation of this vulnerability stems from insufficient validation of user-supplied data during JB2 file parsing operations. When the PDF-XChange Editor processes a JB2 file, it fails to properly validate the size and structure of the image data before attempting to read from memory locations. This lack of input validation creates an opportunity for attackers to craft malicious JB2 files that contain malformed data structures designed to trigger the out-of-bounds read condition. The vulnerability's exploitation mechanism involves manipulating the JB2 file's internal data structures to cause the parser to access memory beyond the allocated buffer boundaries. This type of vulnerability is particularly concerning because it can be combined with other exploits to create more sophisticated attack chains, potentially leading to full system compromise. The ATT&CK framework categorizes this vulnerability under T1059.007 for process injection techniques and T1566 for spearphishing attacks, as the user interaction requirement aligns with social engineering tactics. The specific memory access patterns involved in this vulnerability can reveal information about the application's memory layout, which can be instrumental in bypassing modern security protections such as address space layout randomization and data execution prevention mechanisms.
The operational impact of CVE-2024-8823 extends beyond immediate information disclosure to encompass potential system compromise and data breaches. Organizations using PDF-XChange Editor are at risk of unauthorized access to sensitive information stored in memory, including but not limited to user credentials, session tokens, or proprietary data. The vulnerability's potential for arbitrary code execution means that attackers could gain complete control over affected systems, leading to data exfiltration, system infiltration, or deployment of additional malware. The attack surface is particularly broad since JB2 files are commonly embedded within PDF documents, making this vulnerability accessible through multiple vectors including email attachments, web downloads, and document sharing platforms. Security teams must consider the broader implications of this vulnerability within their enterprise environments, as it could be exploited in targeted attacks against high-value targets or in mass phishing campaigns. The vulnerability's classification as ZDI-CAN-24261 indicates that it has been formally recognized by the Zero Day Initiative, highlighting its significance in the cybersecurity community. Organizations should prioritize patch management and user education to mitigate the risk, as the vulnerability requires no privileged access to exploit and can be effectively delivered through common attack vectors such as malicious email attachments or compromised websites. The vulnerability's remediation involves implementing proper bounds checking and input validation mechanisms within the JB2 file parsing code, ensuring that all user-supplied data is thoroughly validated before memory access operations occur.
Mitigation strategies for CVE-2024-8823 should focus on both immediate protective measures and long-term architectural improvements. Organizations should implement network-based protections such as web application firewalls and content filtering systems to detect and block malicious JB2 files before they reach end users. The immediate priority should be applying vendor-provided patches and updates as soon as they become available, since the vulnerability is actively being exploited in the wild. User education programs should emphasize the importance of verifying document sources and avoiding suspicious email attachments or web downloads that may contain malicious JB2 files. Security monitoring should include detection of unusual memory access patterns or file parsing activities that could indicate exploitation attempts. Implementing principle of least privilege access controls and regular security audits can help minimize the potential damage from successful exploitation attempts. Additionally, organizations should consider deploying sandboxing technologies that isolate PDF processing activities in isolated environments, preventing malicious code from directly accessing system resources. The vulnerability's nature makes it particularly suitable for exploit mitigation through memory protection mechanisms such as stack canaries, heap metadata protection, and address space layout randomization. Regular security assessments and penetration testing should include evaluation of file parsing components to identify similar vulnerabilities that may exist within other document processing software. The implementation of automated threat intelligence feeds can help organizations stay ahead of emerging threats by providing early warnings about exploitation attempts targeting this vulnerability. Organizations should also consider implementing endpoint detection and response solutions that can monitor for suspicious file parsing activities and alert security teams to potential exploitation attempts.