CVE-2018-17701 in PhantomPDF
Summary
by MITRE
This vulnerability allows remote attackers to execute arbitrary code on vulnerable installations of Foxit PhantomPDF 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 JSON objects. 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 vulnerability to execute code in the context of the current process. Was ZDI-CAN-7132.
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Analysis
by VulDB Data Team • 08/01/2024
CVE-2018-17701 represents a critical buffer over-read vulnerability affecting Foxit PhantomPDF version 9.2.0.9297 that enables remote code execution through improper JSON object handling. This vulnerability falls under the CWE-125 category of out-of-bounds read conditions, where the software fails to properly validate user-supplied data during JSON parsing operations. The flaw occurs when the application processes malformed JSON objects without adequate bounds checking, leading to memory access violations that can be exploited by attackers to read beyond allocated memory boundaries.
The exploitation of this vulnerability requires user interaction, meaning that victims must either visit a malicious webpage or open a specially crafted malicious file containing the vulnerable JSON data. This attack vector aligns with the ATT&CK technique T1203 - Exploitation for Client Execution, where adversaries leverage application vulnerabilities to execute code on targeted systems. The vulnerability exists in the PDF processing engine's JSON parser, which does not properly validate the length and structure of incoming JSON data before attempting to access memory locations.
From an operational impact perspective, successful exploitation of CVE-2018-17701 allows attackers to execute arbitrary code with the privileges of the current user process, potentially leading to full system compromise. The vulnerability's remote nature makes it particularly dangerous as it can be triggered through web browsing activities without requiring local system access. Attackers can leverage this to deploy malware, establish backdoors, or perform further reconnaissance within the compromised network environment.
Security mitigations for this vulnerability should focus on immediate patching of affected Foxit PhantomPDF installations to version 9.2.1.1 or later, which contains the necessary fixes for the JSON parsing logic. Organizations should also implement network-based protections such as web application firewalls and content filtering systems to block access to known malicious domains. Additionally, user education regarding the dangers of visiting untrusted websites and opening suspicious email attachments remains crucial. The vulnerability demonstrates the importance of proper input validation and bounds checking in software development, particularly in applications that process untrusted data from external sources. This case study highlights the necessity of following secure coding practices and implementing defensive programming techniques to prevent buffer over-read conditions that can lead to remote code execution exploits.