CVE-2018-17661 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 messageBox method of a Host object. 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-6513.
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Analysis
by VulDB Data Team • 05/05/2020
CVE-2018-17661 represents a critical remote code execution vulnerability affecting Foxit Reader version 9.2.0.9297, classified under CWE-476 as "NULL Pointer Dereference" within the context of improper object validation. This vulnerability resides in the messageBox method of a Host object, where the application fails to validate whether an object exists before attempting operations on it. The flaw stems from inadequate input validation and object lifecycle management, creating a condition where a null pointer dereference can occur during the processing of maliciously crafted PDF content. The vulnerability requires user interaction to be exploited, meaning that an attacker must convince a victim to visit a malicious webpage or open a specially crafted malicious file containing the vulnerable code. This attack vector aligns with ATT&CK technique T1203, "Exploitation for Client Execution," where adversaries leverage vulnerabilities in applications to execute malicious code in the context of the targeted user's session. The security implications are severe as successful exploitation allows attackers to execute arbitrary code with the privileges of the current process, potentially leading to full system compromise. The vulnerability demonstrates poor defensive programming practices where object validation checks are missing or insufficient, enabling attackers to manipulate the application's execution flow through carefully crafted input that triggers the null pointer dereference condition. This type of vulnerability is particularly dangerous in PDF readers due to their widespread use and the complex nature of PDF parsing, where a single malformed element can trigger unexpected behavior in the underlying application engine. The issue has been addressed through proper input validation and object existence checks, emphasizing the importance of defensive programming principles in preventing such remote code execution scenarios. Organizations should ensure immediate patching of affected Foxit Reader installations and implement network-based protections such as web application firewalls and content filtering to prevent access to malicious PDF content. The vulnerability also highlights the need for comprehensive security testing including fuzzing and static code analysis to identify similar object validation flaws in similar applications. This case study exemplifies how seemingly minor validation oversights can create significant security risks, particularly in applications that process untrusted input from the internet, underscoring the critical importance of robust input validation and proper error handling in security-critical software components. The flaw's impact extends beyond simple code execution to potentially enable privilege escalation attacks, where the executed code could leverage additional system capabilities based on the user's permissions and the application's security context.