CVE-2018-17686 in Foxit
Summary
by MITRE
This vulnerability allows remote attackers to disclose sensitive information 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 processing of BMP images. 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 buffer. An attacker can leverage this vulnerability to execute code in the context of the current process. Was ZDI-CAN-6844.
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Analysis
by VulDB Data Team • 07/31/2024
The vulnerability identified as CVE-2018-17686 represents a critical buffer over-read flaw in Foxit Reader version 9.2.0.9297 that enables remote code execution through malicious BMP image processing. This vulnerability falls under the Common Weakness Enumeration category CWE-125, which describes out-of-bounds read conditions where a program reads data past the end of a buffer, potentially exposing sensitive memory contents. The flaw specifically manifests during the handling of BMP image files, making it particularly dangerous in environments where users may encounter untrusted image content through web browsing or email attachments. The vulnerability requires user interaction to be exploited, meaning an attacker must convince a target to visit a malicious webpage or open a compromised document containing the malicious BMP file. This social engineering component aligns with ATT&CK technique T1203, which involves the use of malicious files to gain initial access to systems.
The technical implementation of this vulnerability occurs within the BMP image parsing functionality of Foxit Reader, where insufficient input validation leads to a buffer over-read condition. When processing a specially crafted BMP file, the application fails to properly validate the image data structure, allowing an attacker to manipulate the parsing logic to read beyond allocated memory boundaries. This improper validation creates a scenario where attacker-controlled data can influence memory access patterns, potentially exposing sensitive information such as stack canaries, heap metadata, or other process memory contents. The read past the end of a buffer condition provides attackers with the opportunity to gather information that could be used for further exploitation, including bypassing modern memory protection mechanisms like DEP and ASLR. The vulnerability's exploitation potential extends beyond simple information disclosure to full remote code execution, as the leaked memory information can be leveraged to defeat security features and craft successful attack payloads.
The operational impact of this vulnerability is significant for organizations using Foxit Reader, particularly those with users who frequently access untrusted web content or receive email attachments from unknown sources. The requirement for user interaction limits the automated exploitation potential but does not eliminate the risk entirely, as social engineering campaigns can effectively target specific user groups. Organizations that rely on Foxit Reader for document viewing in environments where security is paramount face increased risk of targeted attacks, especially when considering that the vulnerability can be triggered through web browsing or document opening activities. The exploitability of this vulnerability is enhanced by the fact that BMP image files are commonly encountered in various contexts, making them an attractive attack vector for threat actors. This vulnerability demonstrates the importance of proper input validation and memory safety practices in document processing applications, as even seemingly benign file formats can serve as entry points for sophisticated attacks.
Mitigation strategies for CVE-2018-17686 should include immediate patching of affected Foxit Reader installations to the latest version that addresses this specific buffer over-read condition. Organizations should implement restrictive file type handling policies that limit the processing of BMP images or other potentially vulnerable formats when they are encountered in untrusted contexts. Network-based defenses should include web filtering solutions that can identify and block access to malicious web pages containing exploit code, while email security solutions should scan for suspicious BMP files in attachments. Additionally, user education programs should emphasize the dangers of visiting untrusted websites or opening unexpected attachments, particularly those containing image files. System administrators should monitor for any signs of exploitation attempts and implement process isolation for document viewing applications to limit the potential impact of successful exploitation. The vulnerability also highlights the need for regular security assessments of document processing applications and the importance of maintaining up-to-date security patches for all software components in the attack surface.