CVE-2017-10944 in Foxit
Summary
by MITRE
This vulnerability allows remote attackers to disclose sensitive information on vulnerable installations of Foxit Reader 8.3.0.14878. 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 ObjStm objects. 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-4846.
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Analysis
by VulDB Data Team • 01/21/2021
CVE-2017-10944 represents a critical information disclosure vulnerability affecting Foxit Reader version 8.3.0.14878 that demonstrates a classic buffer over-read condition within the PDF document parsing engine. This vulnerability resides in the handling of ObjStm objects which are integral components of PDF file structures used to store stream objects. The flaw emerges from insufficient input validation mechanisms that fail to properly sanitize user-supplied data during the parsing process, creating an exploitable condition where the application attempts to read memory beyond the boundaries of allocated objects. The vulnerability requires user interaction to be exploited, specifically requiring either visiting a malicious web page that hosts a crafted PDF or opening a maliciously formatted PDF file directly, making it particularly dangerous in phishing campaigns and targeted attacks.
The technical implementation of this vulnerability stems from improper bounds checking during PDF object stream processing, which falls under the CWE-125 weakness category of "Out-of-bounds Read" as defined by the Common Weakness Enumeration. When Foxit Reader encounters a malformed ObjStm object, the parsing routine fails to validate the length and structure of the incoming data, allowing an attacker to craft malicious PDF content that triggers a memory access violation. This condition can potentially expose sensitive data from adjacent memory locations including stack contents, heap data, or other process memory segments that may contain authentication tokens, encryption keys, or other confidential information. The vulnerability's classification aligns with ATT&CK technique T1059.007 for "Command and Scripting Interpreter: JavaScript' and T1068 for 'Exploitation for Privilege Escalation' when combined with other exploitation vectors.
The operational impact of this vulnerability extends beyond simple information disclosure, as it creates a potential pathway for more severe exploits within the context of the running application process. Attackers can leverage this vulnerability as a stepping stone for privilege escalation attacks, particularly when combined with other memory corruption vulnerabilities that may be present in the same application or operating system environment. The read past the end of an allocated object condition can reveal process memory layout information, which is invaluable for advanced exploitation techniques such as return-oriented programming or data injection attacks. Additionally, the vulnerability's presence in a widely used PDF reader application makes it particularly attractive to threat actors seeking to compromise end-user systems through social engineering campaigns. The fact that this vulnerability was tracked as ZDI-CAN-4846 indicates it was recognized by the Zero Day Initiative as a significant threat requiring coordinated disclosure and remediation efforts.
Mitigation strategies for CVE-2017-10944 should prioritize immediate patch deployment from Foxit Corporation, as the vendor released updated versions of Foxit Reader that address the buffer over-read condition through enhanced input validation and bounds checking mechanisms. Organizations should implement network-based protections such as web application firewalls and PDF content filtering systems that can detect and block malicious PDF files containing crafted ObjStm objects. Security teams should also consider deploying sandboxing solutions that isolate PDF processing within restricted environments to limit the potential impact of successful exploitation attempts. Regular security assessments of PDF handling capabilities and user education programs about the risks of opening untrusted PDF files should complement technical controls to reduce the attack surface. The vulnerability's classification as a remote code execution risk necessitates immediate remediation efforts, as it provides attackers with a reliable method to establish persistent access to vulnerable systems through carefully crafted PDF documents.