CVE-2023-38573 Overview
A use-after-free vulnerability exists in Foxit Reader 12.1.2.15356 that affects how the application handles signature fields within PDF documents. This memory corruption flaw can be triggered through specially crafted JavaScript code embedded in a malicious PDF document, leading to arbitrary code execution on the target system.
Critical Impact
Successful exploitation allows attackers to execute arbitrary code by tricking users into opening a malicious PDF document or visiting a compromised website with the Foxit browser plugin enabled.
Affected Products
- Foxit Reader version 12.1.2.15356
- Systems with Foxit Reader browser plugin extension enabled
Discovery Timeline
- 2023-11-27 - CVE-2023-38573 published to NVD
- 2025-11-04 - Last updated in NVD database
Technical Details for CVE-2023-38573
Vulnerability Analysis
This use-after-free vulnerability (CWE-416) occurs in Foxit Reader's handling of signature fields within PDF documents. When processing certain JavaScript operations related to signature fields, the application improperly manages memory allocation and deallocation, allowing for the reuse of previously freed objects. This memory corruption condition can be leveraged by an attacker to achieve arbitrary code execution with the privileges of the current user.
The vulnerability requires user interaction for exploitation—specifically, the victim must open a malicious PDF file or browse to a specially crafted website while the Foxit Reader browser plugin is active. The attack can be delivered through network-based vectors, making it particularly dangerous for organizations with broad PDF processing workflows.
Root Cause
The root cause of CVE-2023-38573 lies in improper memory management within Foxit Reader's JavaScript engine when processing signature field objects. When a signature field is freed but a reference to it remains, subsequent JavaScript operations can trigger access to the freed memory region. This use-after-free condition creates an exploitable memory corruption scenario.
The vulnerability is classified under CWE-416 (Use After Free), indicating that the application continues to use a pointer after the memory it references has been freed, leading to undefined behavior that attackers can manipulate for code execution.
Attack Vector
The attack vector is network-based and requires user interaction. An attacker can deliver the exploit through two primary methods:
Malicious PDF Document: The attacker crafts a PDF file containing specially designed JavaScript code that manipulates signature field objects to trigger the use-after-free condition. The victim must be tricked into opening this file using Foxit Reader.
Browser Plugin Exploitation: If the Foxit Reader browser plugin is enabled, the attacker can host the malicious PDF on a website and lure victims to visit the page, triggering automatic processing of the malicious document.
The vulnerability allows for complete compromise of confidentiality, integrity, and availability on the affected system. Exploitation does not require any privileges, making it accessible to remote attackers who can successfully deliver the malicious content to potential victims.
Detection Methods for CVE-2023-38573
Indicators of Compromise
- Unexpected crashes or memory access violations in FoxitReader.exe or related processes
- PDF files with suspicious or obfuscated JavaScript code targeting signature field operations
- Unusual child process spawning from Foxit Reader application
- Browser plugin activity downloading or processing PDF files from untrusted sources
Detection Strategies
- Monitor for abnormal memory access patterns in Foxit Reader processes that may indicate use-after-free exploitation
- Implement email and web gateway scanning for PDF documents containing obfuscated JavaScript targeting signature field APIs
- Deploy endpoint detection rules to identify suspicious process behavior following PDF file operations
- Utilize application control policies to alert on unexpected executable launches from PDF reader contexts
Monitoring Recommendations
- Enable enhanced logging for Foxit Reader application events and crash reports
- Configure endpoint protection to monitor for heap manipulation indicators associated with use-after-free attacks
- Establish baseline behavior for PDF processing workflows to identify anomalous activity
- Review browser plugin activity logs for unexpected PDF file processing from untrusted domains
How to Mitigate CVE-2023-38573
Immediate Actions Required
- Upgrade Foxit Reader to the latest patched version that addresses this vulnerability
- Disable the Foxit Reader browser plugin extension until patching is complete
- Configure Foxit Reader to disable JavaScript execution in PDF documents as an interim measure
- Implement user awareness training regarding the risks of opening PDF documents from untrusted sources
Patch Information
Foxit Software has addressed this vulnerability in subsequent releases of Foxit Reader. Organizations should consult the Talos Intelligence Vulnerability Report for detailed information about affected versions and remediation guidance. Ensure that Foxit Reader is updated beyond version 12.1.2.15356 to a patched release.
Workarounds
- Disable JavaScript execution in Foxit Reader by navigating to Preferences > JavaScript and unchecking "Enable JavaScript Actions"
- Disable or remove the Foxit Reader browser plugin to prevent automatic PDF processing from web content
- Use Protected View or Safe Reading Mode features if available in your Foxit Reader version
- Implement network-level filtering to block PDF files from untrusted external sources
# Disable JavaScript in Foxit Reader via registry (Windows)
reg add "HKEY_CURRENT_USER\Software\Foxit Software\Foxit Reader\Preferences\Others" /v bDisableJavaScript /t REG_DWORD /d 1 /f
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
