CVE-2018-17660 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 resetData method of a Host object. 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-6512.
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Analysis
by VulDB Data Team • 05/05/2020
CVE-2018-17660 represents a critical remote code execution vulnerability affecting Foxit Reader version 9.2.0.9297, classified under CWE-476 which specifically addresses null pointer dereference conditions. This vulnerability resides within the Host object's resetData method implementation where the software fails to validate whether an object reference exists before attempting operations on it. The flaw constitutes a fundamental security oversight that allows attackers to manipulate the application's memory management behavior through crafted input. The vulnerability requires user interaction to exploit, meaning a target must either visit a malicious web page or open a specially crafted malicious file to trigger the vulnerable code path. This attack vector aligns with ATT&CK technique T1203, which involves exploitation of web applications through malicious content delivery. The absence of proper object validation creates a window for attackers to inject malicious code that executes within the context of the current process, effectively allowing complete system compromise when the vulnerable application runs with elevated privileges. The vulnerability's impact extends beyond simple code execution as it represents a privilege escalation opportunity that could lead to full system takeover. Attackers can leverage this flaw to bypass security controls and establish persistent access to target systems, making it particularly dangerous in enterprise environments where Foxit Reader is commonly deployed for document processing. The vulnerability demonstrates poor defensive programming practices and highlights the importance of input validation and object existence checks in security-critical applications. This issue specifically affects the PDF rendering engine's handling of malformed data structures, where the resetData method does not properly validate object references before dereferencing them. The exploitation process involves crafting malicious PDF content that triggers the vulnerable Host object behavior, allowing attackers to inject and execute arbitrary code with the privileges of the Foxit Reader process. Organizations using Foxit Reader should prioritize immediate patching as this vulnerability has been actively exploited in the wild. The ZDI-CAN-6512 reference indicates this vulnerability was tracked by the Zero Day Initiative, confirming its significance in the cybersecurity community and the need for urgent remediation. This flaw exemplifies how seemingly minor programming errors in object management can create catastrophic security implications, emphasizing the critical nature of proper defensive programming techniques and thorough code review processes.
The technical exploitation of this vulnerability occurs through a classic null pointer dereference scenario where the resetData method attempts to access memory locations without verifying that the referenced objects are properly initialized. This type of vulnerability commonly appears in applications that handle complex data structures like PDF documents, where various objects may be created, destroyed, or modified during processing. The lack of validation creates a predictable execution flow that attackers can manipulate to redirect program execution to malicious code. The vulnerability's presence in Foxit Reader's PDF processing engine makes it particularly dangerous as PDF files are frequently shared and opened across different systems. This vulnerability's exploitation typically involves crafting a PDF document containing specially formatted data that causes the Host object's resetData method to be called with invalid object references. The resulting memory corruption allows attackers to overwrite critical program execution pointers or inject shellcode directly into the application's memory space. The vulnerability's remote nature means that attackers can deliver malicious payloads through email attachments, web downloads, or compromised websites without requiring physical access to target systems. This characteristic makes it particularly attractive to threat actors conducting large-scale attacks against organizations. The vulnerability's classification under ATT&CK framework as a code execution primitive underscores its potential for enabling more sophisticated attacks such as privilege escalation, lateral movement, or data exfiltration. The impact of this vulnerability extends beyond immediate code execution as it provides attackers with a foothold that can be used to establish persistence mechanisms, escalate privileges, or access sensitive system resources. Organizations should implement network-based mitigations such as web application firewalls and content filtering to prevent access to malicious PDF content while simultaneously applying the vendor-provided patches to eliminate the root cause. The vulnerability demonstrates the importance of secure coding practices and proper input validation in preventing memory corruption issues that can lead to complete system compromise.