CVE-2018-9948 in Foxit
Summary
by MITRE
This vulnerability allows remote attackers to disclose sensitive information on vulnerable installations of Foxit Reader 9.0.0.29935. 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 handling of typed arrays. The issue results from the lack of proper initialization of a pointer prior to accessing it. An attacker can leverage this in conjunction with other vulnerabilities to execute code in the context of the current process. Was ZDI-CAN-5380.
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Analysis
by VulDB Data Team • 04/24/2025
The vulnerability identified as CVE-2018-9948 represents a critical information disclosure flaw affecting Foxit Reader version 9.0.0.29935 and potentially other versions within the same product line. This security weakness resides in the application's handling of typed arrays, which are commonly used in JavaScript environments to manage binary data structures. The vulnerability manifests when the software processes certain array operations without proper initialization of memory pointers, creating a predictable pattern that can be exploited by malicious actors. The flaw specifically impacts the memory management subsystem of the PDF reader, where typed arrays are manipulated during document processing, making it particularly dangerous in the context of PDF exploitation.
The technical implementation of this vulnerability stems from a classic memory safety issue where a pointer variable is accessed before being properly initialized or validated. This type of flaw falls under the CWE-457 category, which specifically addresses the use of uninitialized variables, and is closely related to CWE-125 which deals with out-of-bounds read conditions. When Foxit Reader encounters a maliciously crafted PDF document containing improperly initialized typed arrays, the application attempts to access memory locations that have not been properly allocated or set, leading to information disclosure. The uninitialized pointer access creates a scenario where sensitive data from adjacent memory locations may be inadvertently exposed to the attacker, potentially revealing system memory contents, user data, or other confidential information.
The operational impact of this vulnerability extends beyond simple information disclosure, as it creates a potential attack vector that can be leveraged in combination with other exploits to achieve remote code execution. Attackers can craft malicious PDF documents that trigger the uninitialized pointer access during normal document rendering operations, requiring only user interaction to visit a malicious webpage hosting the document or to open the crafted file. This makes the vulnerability particularly dangerous in enterprise environments where users frequently encounter PDF documents from various sources. The attack chain typically begins with a phishing campaign delivering a specially crafted PDF file, followed by the exploitation of this memory flaw to extract sensitive information and potentially escalate privileges within the application's execution context.
Security professionals should implement multiple layers of defense to mitigate this vulnerability, starting with immediate patching of affected Foxit Reader installations to version 9.0.1.0 or later, which contains the necessary fixes for the uninitialized pointer handling issue. Network-based mitigations can include PDF content filtering and sandboxing solutions that prevent malicious documents from reaching end users, while endpoint protection measures should focus on monitoring for suspicious PDF processing activities. The vulnerability aligns with several ATT&CK techniques including T1059.007 for JavaScript execution and T1068 for local privilege escalation, making it a significant concern for organizations implementing threat hunting and incident response procedures. Additionally, regular security assessments of PDF processing components and comprehensive user education about phishing risks remain essential defensive measures against this and similar memory corruption vulnerabilities.