CVE-2018-9964 in Foxit
Summary
by MITRE
This vulnerability allows remote attackers to execute arbitrary code on vulnerable installations of Foxit Reader 9.0.1.1049. 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 the name attribute of OCG objects. The issue results from the lack of validating the existence of an object prior to performing operations on the object. An attacker can leverage this vulnerability to execute code under the context of the current process. Was ZDI-CAN-5568.
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Analysis
by VulDB Data Team • 02/06/2020
CVE-2018-9964 represents a critical remote code execution vulnerability affecting Foxit Reader version 9.0.1.1049, classified under CWE-476 which denotes "NULL Pointer Dereference" within the Common Weakness Enumeration framework. This vulnerability stems from insufficient input validation during the parsing of the name attribute within Optional Content Group (OCG) objects, creating a dangerous condition where the software attempts to operate on an object that may not exist. The flaw exists at the parsing layer of the PDF processing engine, specifically when handling malformed OCG structures that contain improperly validated name attributes. Attackers can exploit this vulnerability by crafting malicious PDF files containing specially constructed OCG objects that trigger the NULL pointer dereference condition. The vulnerability requires user interaction to be exploited, meaning victims must either visit a malicious webpage hosting the crafted PDF or open the malicious file directly, making it a prime candidate for social engineering attacks. The attack vector operates through the PDF rendering engine's failure to validate object existence before attempting operations on it, allowing attackers to manipulate the execution flow and potentially inject arbitrary code. This type of vulnerability aligns with ATT&CK technique T1203 "Exploitation for Client Execution" which describes how adversaries leverage vulnerabilities in software to execute malicious code on target systems. The security implications extend beyond simple code execution, as the vulnerability allows an attacker to operate under the privileges of the current process, potentially escalating to system-level access depending on the user context. The exploitation process involves manipulating the PDF parser to follow a code path where a null pointer is dereferenced, leading to memory corruption and arbitrary code execution. This vulnerability demonstrates the critical importance of input validation in document processing applications, as PDF readers must handle untrusted content from various sources without compromising system integrity. The flaw specifically affects the object model handling within Foxit Reader's PDF engine, where the name attribute of OCG objects is processed without proper validation of object existence, creating a predictable crash condition that can be leveraged for code execution. The vulnerability's impact is amplified by the widespread use of Foxit Reader in enterprise environments, where users may encounter malicious PDF files through email attachments, web downloads, or compromised websites. Security researchers have identified that this vulnerability could be exploited through techniques such as heap spraying or return-oriented programming to achieve reliable code execution. The exploitation requires precise control over memory layout and object references, making it particularly dangerous in modern security environments where address space layout randomization and other mitigations are in place. Organizations using Foxit Reader should implement immediate patching strategies, as this vulnerability represents a significant risk to information security. The vulnerability also highlights the broader category of memory safety issues in PDF processing engines, which have historically been prone to such flaws due to the complex nature of PDF format parsing and the need to support extensive functionality. Mitigation strategies should include user education about suspicious PDF files, network-based filtering of PDF content, and application whitelisting where possible. The vulnerability underscores the critical importance of proper object validation in document processing software and demonstrates why security-conscious development practices must be implemented throughout the software lifecycle to prevent such dangerous conditions from occurring in production systems.