CVE-2018-17644 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 addItem method 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-6481.
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Analysis
by VulDB Data Team • 05/05/2020
CVE-2018-17644 represents a critical remote code execution vulnerability affecting Foxit Reader version 9.2.0.9297 that demonstrates a classic improper input validation flaw categorized under CWE-476. This vulnerability resides within the TimeField class's addItem method where the application fails to validate whether an object reference exists before attempting to perform operations on it. The flaw constitutes a null pointer dereference condition that can be exploited by remote attackers who craft malicious PDF documents containing specifically formatted TimeField objects. The vulnerability requires user interaction to be successfully exploited, meaning victims must either visit a malicious webpage hosting the crafted PDF or directly open the malicious file, making this a typical client-side attack vector that aligns with ATT&CK technique T1203 for Exploitation for Client Execution.
The technical implementation of this vulnerability stems from inadequate object validation within the PDF rendering engine's TimeField handling logic. When the addItem method processes TimeField objects, it assumes the existence of certain object references without proper null checks, creating a scenario where a maliciously crafted PDF can trigger a memory access violation that allows arbitrary code execution. This type of vulnerability falls under the broader category of heap-based buffer overflows and memory corruption issues that have historically been exploited in PDF readers due to the complex nature of PDF parsing and object handling. The vulnerability's exploitation occurs in the context of the current process, meaning that successful exploitation would allow attackers to execute malicious code with the privileges and permissions of the Foxit Reader application, potentially leading to full system compromise.
The operational impact of CVE-2018-17644 extends beyond simple remote code execution as it provides attackers with a persistent foothold within targeted environments. Organizations using Foxit Reader 9.2.0.9297 are particularly vulnerable since this version represents a widely deployed client-side PDF viewer that processes untrusted PDF content from various sources. The vulnerability's remote nature means that attackers can leverage it through web-based attack vectors, social engineering campaigns, or compromised websites that serve malicious PDF documents. This creates significant risk for enterprise environments where users frequently access external websites or receive PDF attachments from unknown sources, making the vulnerability particularly dangerous in phishing scenarios and targeted attacks. The lack of automatic patching mechanisms in client applications further compounds the risk, as organizations must rely on user awareness and manual updates to mitigate the threat.
Mitigation strategies for CVE-2018-17644 should focus on immediate patch management and defensive measures that address the root cause of the vulnerability. Organizations must prioritize updating Foxit Reader installations to versions that contain the patched TimeField handling logic, which typically involves implementing proper null pointer validation before object operations. Network-level defenses such as web application firewalls and PDF content filtering solutions can provide additional protection by scanning and blocking malicious PDF files before they reach end users. Security awareness training programs should emphasize the importance of avoiding suspicious PDF attachments and websites, while endpoint protection solutions should be configured to monitor for unusual process execution patterns that might indicate exploitation attempts. The vulnerability's classification as a client-side exploit also necessitates implementation of principle of least privilege configurations where PDF readers operate with minimal system privileges to limit potential damage from successful exploitation attempts. Additionally, organizations should consider implementing sandboxing technologies for PDF processing to isolate potentially malicious content and prevent code execution from affecting the core operating system.