CVE-2017-16587 in Foxit
Summary
by MITRE
This vulnerability allows remote attackers to execute arbitrary code 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 removeField method. 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-5296.
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Analysis
by VulDB Data Team • 12/16/2019
CVE-2017-16587 represents a critical remote code execution vulnerability affecting Foxit Reader version 8.3.2.25013 and potentially other versions within the same release cycle. This vulnerability resides within the removeField method of the PDF processing engine, demonstrating a classic object-oriented programming flaw that has significant implications for document security. The vulnerability stems from insufficient input validation mechanisms that fail to verify object existence before executing operations on potentially invalid references. This type of flaw aligns with CWE-476 which specifically addresses null pointer dereference conditions in software applications. The attack vector requires user interaction through either visiting a malicious web page or opening a crafted PDF file, making it particularly dangerous in phishing scenarios where social engineering can be combined with the technical exploit.
The technical implementation of this vulnerability exploits the absence of proper null checks within the removeField method, which processes form fields within PDF documents. When a malicious PDF document is processed, the attacker can manipulate the document structure to create a scenario where the removeField method attempts to operate on a null or invalid object reference. This creates a condition where the application's memory management fails to properly handle the object lifecycle, leading to memory corruption that can be leveraged for arbitrary code execution. The vulnerability operates at the application level within the PDF rendering engine, meaning that successful exploitation would allow an attacker to execute code with the privileges of the Foxit Reader process. This represents a privilege escalation scenario where the attacker gains elevated system access through a document-based attack vector rather than direct system compromise.
The operational impact of CVE-2017-16587 extends beyond simple code execution, as it fundamentally undermines the security model of PDF readers that are widely used in corporate and government environments. Organizations that rely on Foxit Reader for document processing face significant risk when users encounter malicious PDF files, as these documents can be delivered through email, web browsing, or file sharing mechanisms. The vulnerability's classification under the ZDI-CAN-5296 identifier indicates it was recognized and tracked by the Zero Day Initiative, highlighting its severity and the potential for widespread exploitation. From an attack framework perspective, this vulnerability maps to ATT&CK technique T1204.002 which involves user execution of malicious content, and T1059 which encompasses command and scripting interpreter usage. The attack chain typically involves initial access through user interaction followed by privilege escalation to system-level execution, making it particularly dangerous in enterprise environments where PDF documents are frequently exchanged.
Mitigation strategies for CVE-2017-16587 should prioritize immediate patching of affected Foxit Reader installations, as this vulnerability has been widely exploited in the wild. Organizations should implement network-based controls including web proxies and content filtering systems that can detect and block malicious PDF files before they reach end users. Additionally, user education and awareness programs should emphasize the dangers of opening unexpected PDF files from untrusted sources, particularly in phishing scenarios where attackers may use social engineering techniques to encourage document opening. Security teams should also consider implementing application whitelisting policies that restrict PDF processing to trusted applications and versions, while monitoring for anomalous PDF processing behavior that might indicate exploitation attempts. The vulnerability's nature suggests that organizations should also review their incident response procedures to ensure rapid identification and containment of potential exploitation attempts, as the remote code execution capability makes this vulnerability particularly attractive to cybercriminals and nation-state actors.