CVE-2017-14822 in Foxit
Summary
by MITRE
This vulnerability allows remote attackers to disclose sensitive information on vulnerable installations of Foxit Reader 8.3.1.21155. 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 parsing of the xOsiz member of SIZ markers. 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 code in the context of the current process. Was ZDI-CAN-5014.
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Analysis
by VulDB Data Team • 12/16/2019
CVE-2017-14822 represents a critical information disclosure vulnerability affecting Foxit Reader version 8.3.1.21155 that demonstrates a classic buffer over-read condition within the PDF parsing functionality. This vulnerability resides in the handling of the xOsiz member within SIZ markers, which are part of the PDF file structure used for specifying object sizes. The flaw stems from insufficient input validation where the application fails to properly verify the boundaries of user-supplied data during the parsing process, leading to memory access violations that can expose sensitive information from adjacent memory locations.
The technical implementation of this vulnerability involves the parser's failure to validate the size parameter xOsiz before using it to calculate memory access offsets. When processing malformed PDF files containing crafted SIZ markers, the application's memory management routines execute calculations that extend beyond the allocated buffer boundaries, resulting in a read past the end of an allocated object. This condition creates a potential information leak that could expose cryptographic keys, temporary passwords, or other sensitive data stored in adjacent memory segments. The vulnerability specifically aligns with CWE-125, which describes out-of-bounds read conditions, and demonstrates the dangerous intersection of improper input validation and memory access control.
From an operational perspective, exploitation of this vulnerability requires user interaction through either visiting a malicious webpage hosting a crafted PDF file or opening a specially crafted document. This makes the attack surface more manageable compared to fully autonomous exploits but still represents a significant risk in enterprise environments where users frequently interact with untrusted PDF content. The vulnerability's classification as a remote code execution vector through combination with other weaknesses means that an attacker could potentially chain this issue with additional vulnerabilities to achieve full system compromise. This scenario aligns with ATT&CK technique T1059.007 for execution through PDF files and T1068 for privilege escalation.
The impact of this vulnerability extends beyond simple information disclosure to potentially enable more sophisticated attacks that leverage the leaked memory contents for further exploitation. Attackers could use the exposed information to bypass security mechanisms, discover system configurations, or gather intelligence for targeted attacks. The vulnerability's presence in a widely used PDF reader application makes it particularly dangerous as it could affect thousands of endpoints across various industries. Organizations should prioritize patching this vulnerability and implement additional security controls such as PDF sandboxing, content filtering, and user education programs to reduce the risk of successful exploitation. The vulnerability also highlights the importance of proper memory safety practices and input validation in document processing applications, particularly those handling untrusted binary data formats like PDF files.