CVE-2018-9971 in Foxit
Summary
by MITRE
This vulnerability allows remote attackers to disclose sensitive information on vulnerable installations of Foxit Reader 9.0.1.104. 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 ConvertToPDF_x86.dll. 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 in conjunction with other vulnerabilities to execute arbitrary code in the context of the current process. Was ZDI-CAN-5754.
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Analysis
by VulDB Data Team • 08/15/2024
CVE-2018-9971 represents a critical information disclosure vulnerability affecting Foxit Reader version 9.0.1.104 that resides within the ConvertToPDF_x86.dll component. This vulnerability manifests as a buffer over-read condition that occurs when the application processes user-supplied data without adequate validation mechanisms. The flaw stems from improper input sanitization where the software fails to properly bounds-check data structures during PDF conversion operations, leading to memory access violations that can expose sensitive information stored in adjacent memory regions.
The technical exploitation of this vulnerability requires user interaction through either visiting a malicious webpage or opening a specially crafted malicious file that triggers the vulnerable ConvertToPDF_x86.dll module. This attack vector aligns with common web-based exploitation techniques and represents a classic example of a buffer overflow vulnerability that can be leveraged for information disclosure attacks. The read past the end of an allocated object condition creates opportunities for attackers to extract potentially sensitive data from memory locations that should remain protected, including stack contents, heap data, or other application state information.
From an operational impact perspective, this vulnerability presents significant risks to organizations using Foxit Reader as their primary PDF processing tool. The ability to disclose sensitive information through memory read operations can expose cryptographic keys, session tokens, application credentials, or other confidential data that resides in memory during processing. The vulnerability's classification under CWE-125 - "Out-of-bounds Read" demonstrates its fundamental nature as a memory safety issue that can be exploited to gain insights into application internals. This information disclosure capability can serve as a stepping stone for more sophisticated attacks, potentially enabling attackers to perform further exploitation techniques such as stack spraying or heap manipulation.
The vulnerability's exploitation complexity is relatively low since it requires only user interaction to trigger the malicious code path, making it particularly dangerous in targeted attack scenarios or when combined with other vulnerabilities. Security professionals should note that this issue was tracked as ZDI-CAN-5754, indicating its recognition by the Zero Day Initiative and highlighting its potential impact within the broader security community. Organizations should prioritize patching this vulnerability through official Foxit updates, as the exploitability of buffer over-read conditions often increases when combined with other vulnerabilities in exploit chains, potentially leading to full system compromise.
Mitigation strategies should include immediate deployment of Foxit Reader patches, implementation of web application firewalls to block malicious content, and user education regarding the dangers of visiting untrusted websites or opening suspicious files. Network segmentation and monitoring for unusual memory access patterns can help detect exploitation attempts. The vulnerability demonstrates the importance of proper input validation and bounds checking in preventing memory safety issues, aligning with ATT&CK technique T1059.007 for execution through scriptlets and T1566 for social engineering attacks that leverage user interaction. Security teams should also consider implementing exploit prevention measures such as DEP, ASLR, and code signing enforcement to reduce the overall attack surface and prevent successful exploitation of similar memory corruption vulnerabilities.