CVE-2018-17648 in Foxit
Summary
by MITRE
This vulnerability allows remote attackers to execute arbitrary code on vulnerable installations of Foxit Reader 9.2.0.9297. 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 the rotate property of a TimeField. 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 in the context of the current process. Was ZDI-CAN-6485.
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Analysis
by VulDB Data Team • 05/05/2020
CVE-2018-17648 represents a critical buffer overflow vulnerability affecting Foxit Reader version 9.2.0.9297 that enables remote code execution through crafted PDF documents. This vulnerability falls under the CWE-476 category of Null Pointer Dereference, where the application fails to validate object existence before performing operations on it. The flaw specifically manifests in the handling of TimeField objects within PDF documents, particularly when processing the rotate property. Attackers can exploit this by crafting malicious PDF files containing specially constructed TimeField elements that trigger the vulnerable code path. The vulnerability requires user interaction to be successfully exploited, meaning victims must open the malicious file or visit a web page hosting the compromised content. This attack vector aligns with ATT&CK technique T1203, which describes exploitation of software vulnerabilities through malicious files. The root cause stems from inadequate input validation within the PDF parsing engine, where the application assumes certain objects exist without proper verification before dereferencing pointers. When the rotate property of a TimeField is processed, the application attempts to access memory locations without confirming that the underlying object reference is valid, leading to potential memory corruption. This flaw allows attackers to execute arbitrary code with the privileges of the currently running Foxit Reader process, potentially enabling full system compromise. The vulnerability is particularly concerning because PDF readers are commonly used applications that users trust, making social engineering attacks more effective. Security researchers have identified that the flaw exists in the PDF document parser's handling of embedded JavaScript and form field properties, where insufficient bounds checking and object validation creates opportunities for exploitation. The impact extends beyond simple code execution to potentially allow privilege escalation, data theft, and persistent backdoor installation. Organizations should prioritize patching this vulnerability as it represents a significant risk to endpoint security and could be leveraged in advanced persistent threat campaigns.
The technical implementation of this vulnerability demonstrates poor defensive programming practices where the application fails to implement proper null pointer checks before object manipulation. The TimeField rotate property handling represents a classic example of insufficient input sanitization, where the PDF parser does not validate that all referenced objects exist before attempting to access their properties. This type of vulnerability commonly occurs in applications that parse complex binary formats without adequate error handling mechanisms. The exploitation process typically involves crafting a PDF document with malformed TimeField elements that cause the parser to attempt operations on null or invalid object references. This creates a memory access violation that can be manipulated to redirect execution flow, allowing attackers to inject and execute malicious code. The vulnerability's classification as a remote code execution flaw means that attackers can deliver malicious payloads through various attack vectors including web browsers, email attachments, or file sharing platforms. The ZDI-CAN-6485 reference indicates this vulnerability was identified and tracked by the Zero Day Initiative, highlighting its significance in the cybersecurity community. From a defensive perspective, organizations should implement multiple layers of protection including web application firewalls, email filtering solutions, and regular security updates to mitigate exposure. The vulnerability also underscores the importance of sandboxing PDF readers and implementing least privilege principles to limit the potential impact of successful exploits. Network segmentation and user education remain critical components in reducing the attack surface and preventing exploitation of such vulnerabilities.