CVE-2017-16580 in Foxit
Summary
by MITRE
This vulnerability allows remote attackers to disclose sensitive information on vulnerable installations of Foxit Reader 8.3.2.25013. 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 ImageField node of XFA forms. 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 code in the context of the current process. Was ZDI-CAN-5281.
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Analysis
by VulDB Data Team • 01/27/2021
The vulnerability identified as CVE-2017-16580 represents a critical information disclosure flaw affecting Foxit Reader version 8.3.2.25013 and potentially other versions within the same release cycle. This security weakness resides within the XFA form processing functionality of the PDF reader application, specifically within the ImageField node implementation. The vulnerability demonstrates characteristics consistent with a buffer over-read condition that can be exploited remotely by attackers who successfully convince victims to interact with malicious content. The flaw fundamentally stems from inadequate input validation mechanisms that fail to properly sanitize user-supplied data during the processing of XFA form elements, particularly those involving image field components.
The technical implementation of this vulnerability occurs when Foxit Reader processes malicious XFA forms containing specially crafted ImageField nodes. The absence of proper bounds checking allows the application to read memory locations beyond the allocated buffer boundaries, potentially exposing sensitive data from adjacent memory regions. This type of flaw falls under the CWE-125 vulnerability category, which specifically addresses out-of-bounds read conditions in software implementations. The vulnerability's exploitation requires user interaction through either visiting a malicious web page that loads a crafted PDF or opening a maliciously prepared PDF file containing the vulnerable XFA structure. The attack vector demonstrates the classic characteristics of a client-side exploit where the victim's browser or PDF reader application becomes the attack surface for information disclosure and potential code execution.
The operational impact of CVE-2017-16580 extends beyond simple information disclosure to encompass potential code execution capabilities within the context of the current process. When combined with other vulnerabilities present in the same software environment or exploited through additional attack vectors, this flaw can enable adversaries to achieve arbitrary code execution with the privileges of the Foxit Reader application. This represents a significant escalation from a simple information disclosure vulnerability to a full remote code execution threat that can compromise entire systems. The vulnerability's classification aligns with ATT&CK technique T1203, which involves exploitation of software vulnerabilities for privilege escalation and code execution. The affected Foxit Reader application creates a persistent threat vector where legitimate users may inadvertently encounter malicious content through email attachments, web downloads, or compromised websites, making this vulnerability particularly dangerous in enterprise environments where PDF processing is common.
Mitigation strategies for this vulnerability should prioritize immediate patching of affected Foxit Reader installations to the latest available versions that contain the necessary security fixes. Organizations should implement network-based controls such as web application firewalls and content filtering solutions to prevent access to known malicious domains that may host exploit content. Additionally, security awareness training for end users should emphasize the dangers of opening unexpected PDF files or visiting untrusted websites that may contain malicious XFA forms. System administrators should consider implementing sandboxing mechanisms for PDF processing and monitoring for unusual memory access patterns that may indicate exploitation attempts. The vulnerability's presence in the XFA form processing subsystem highlights the importance of validating all user-supplied content and implementing comprehensive input sanitization measures to prevent similar issues in other software components. Organizations should also consider maintaining detailed logs of PDF processing activities and implementing automated scanning for potentially malicious XFA structures to detect and respond to exploitation attempts before they can cause significant damage to the network infrastructure.