CVE-2016-4059 in Foxit
Summary
by MITRE
Use-after-free vulnerability in Foxit Reader and PhantomPDF before 7.3.4 on Windows allows remote attackers to execute arbitrary code via a crafted FlateDecode stream in a PDF document.
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Analysis
by VulDB Data Team • 10/21/2018
The vulnerability identified as CVE-2016-4059 represents a critical use-after-free flaw affecting Foxit Reader and PhantomPDF versions prior to 7.3.4 on Windows operating systems. This vulnerability resides in the handling of PDF documents and specifically targets the FlateDecode stream processing functionality within the PDF rendering engine. The flaw enables remote attackers to craft malicious PDF documents that can trigger arbitrary code execution when the affected software processes these documents, making it a significant threat vector for targeted attacks and exploit campaigns.
The technical nature of this vulnerability stems from improper memory management within the PDF parsing components of these applications. When processing a specially crafted FlateDecode stream, the software fails to properly validate or manage memory references, leading to a situation where freed memory locations are accessed after they have been deallocated. This use-after-free condition creates a predictable memory corruption scenario that attackers can leverage to inject and execute malicious code within the context of the running application. The vulnerability specifically impacts the PDF decompression and rendering pipeline where FlateDecode streams are processed, making it particularly dangerous when users open or preview PDF documents from untrusted sources.
The operational impact of CVE-2016-4059 extends beyond simple remote code execution to encompass potential privilege escalation and system compromise scenarios. Attackers can exploit this vulnerability by delivering malicious PDF documents through various attack vectors including email attachments, web downloads, or compromised websites. Once executed, the malicious code operates with the privileges of the affected application, potentially allowing attackers to gain unauthorized access to sensitive data, install additional malware, or establish persistent access to compromised systems. This vulnerability aligns with CWE-416, which describes the use of freed memory conditions, and represents a classic example of how improper memory management can lead to severe security consequences. The attack surface is particularly broad as PDF documents are commonly shared across organizations and individuals, making this vulnerability highly attractive to threat actors.
Organizations and users should prioritize immediate remediation by upgrading to Foxit Reader and PhantomPDF version 7.3.4 or later, which contains the necessary patches to address this vulnerability. Additional mitigations include implementing strict PDF document filtering policies, enabling sandboxing features where available, and deploying network-based intrusion detection systems to monitor for exploitation attempts. Security teams should also consider implementing email filtering solutions that can detect and block suspicious PDF attachments, particularly those containing obfuscated or malformed FlateDecode streams. The vulnerability demonstrates the importance of proper memory management in security-critical applications and underscores the need for regular security updates and vulnerability assessments. This issue is also categorized under ATT&CK technique T1059.007 for command and scripting interpreter and T1203 for Exploitation for Client Execution, highlighting its role in lateral movement and persistent access within compromised environments.