CVE-2018-17623 in Foxit
Summary
by MITRE
This vulnerability allows remote attackers to execute arbitrary code on vulnerable installations of Foxit Reader 9.0.1.5096. 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 Link objects. 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-6434.
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Analysis
by VulDB Data Team • 04/07/2020
CVE-2018-17623 represents a critical remote code execution vulnerability affecting Foxit Reader version 9.0.1.5096, classified under CWE-476 as Null Pointer Dereference. This vulnerability stems from insufficient input validation within the PDF document parser's handling of Link objects, specifically when processing malformed or crafted PDF files. The flaw occurs when the application attempts to perform operations on a Link object without first verifying its existence or proper initialization, creating a dangerous condition where memory access violations can be exploited by malicious actors.
The technical exploitation of this vulnerability requires user interaction through either visiting a malicious web page that loads a compromised PDF document or opening a specially crafted malicious file. This attack vector aligns with ATT&CK technique T1203 - Exploitation for Client Execution, as it leverages the PDF reader's parsing functionality to deliver malicious payloads. The vulnerability allows attackers to execute arbitrary code within the context of the Foxit Reader process, potentially enabling full system compromise depending on the privileges of the affected user. The null pointer dereference condition creates a predictable memory access pattern that can be leveraged for privilege escalation and code injection attacks.
From an operational standpoint, this vulnerability presents significant risk to organizations relying on Foxit Reader for document processing, as it can be exploited through social engineering campaigns targeting end users. The impact extends beyond individual user compromise to potential network-wide infiltration, especially when users access untrusted web content or download documents from unknown sources. Security teams must consider the widespread deployment of Foxit Reader across enterprise environments, where this vulnerability could serve as an initial access point for more sophisticated attacks. The vulnerability's classification as a remote code execution flaw means that attackers do not require physical access to target systems, making it particularly dangerous in environments with limited network segmentation.
Organizations should implement immediate mitigations including updating to Foxit Reader version 9.1.0.1731 or later, which contains the necessary patches to address the null pointer dereference issue. Network administrators should consider implementing web filtering solutions to block access to known malicious domains and content, while endpoint protection measures should be configured to monitor for suspicious PDF file handling activities. The vulnerability's exploitation requires user interaction, so security awareness training becomes crucial to prevent users from opening suspicious PDF files or visiting malicious websites. Additionally, system hardening measures such as disabling unnecessary PDF features and implementing application whitelisting can reduce the attack surface. Organizations should also monitor for indicators of compromise related to PDF file access patterns and consider implementing sandboxing techniques for PDF document processing to contain potential exploitation attempts.