CVE-2015-3633 in Foxit
Summary
by MITRE
Foxit Reader, Enterprise Reader, and PhantomPDF before 7.1.5 allow remote attackers to cause a denial of service (memory corruption and crash) via vectors related to digital signatures.
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Analysis
by VulDB Data Team • 05/10/2022
CVE-2015-3633 represents a critical memory corruption vulnerability affecting Foxit Reader, Enterprise Reader, and PhantomPDF versions prior to 7.1.5. This vulnerability stems from improper handling of digital signature objects within PDF documents, creating a condition where malformed or specially crafted digital signatures can trigger heap-based buffer overflows or use-after-free conditions in the application's memory management routines. The flaw manifests when the affected software processes digital signature data structures, particularly during the verification or rendering phases of PDF documents containing malicious signature elements.
The technical execution of this vulnerability involves attackers crafting PDF files with malformed digital signature objects that exploit memory corruption patterns in the Foxit PDF processing engine. When the vulnerable applications attempt to parse these signatures, they fail to properly validate input boundaries or maintain proper memory state management, leading to unauthorized memory access patterns that result in application crashes or potential arbitrary code execution. This behavior aligns with CWE-125, which describes out-of-bounds read conditions, and CWE-476, which covers null pointer dereference vulnerabilities commonly found in memory management functions.
From an operational perspective, this vulnerability presents significant risk to organizations relying on Foxit PDF readers for document processing, as remote attackers can exploit it through simple PDF file delivery mechanisms such as email attachments or web downloads. The denial of service impact extends beyond mere application crashes, potentially creating persistent availability issues for users who depend on these PDF processing tools for business-critical workflows. The vulnerability's remote exploitability means that attackers do not require physical access to target systems, making it particularly dangerous in enterprise environments where PDF documents are frequently shared and opened by multiple users.
The mitigation strategy for CVE-2015-3633 primarily involves immediate deployment of Foxit Reader version 7.1.5 or later, which includes patched memory handling routines for digital signature processing. Organizations should also implement network-based controls such as PDF content filtering and sandboxing mechanisms to prevent exploitation attempts. Additionally, security teams should monitor for any related attack patterns in their network traffic and consider implementing endpoint protection solutions that can detect and block malicious PDF files before they reach end-user systems. This vulnerability demonstrates the importance of maintaining current software versions and implementing defense-in-depth strategies to protect against memory corruption exploits that can lead to both denial of service and potential privilege escalation scenarios.