CVE-2024-7725 Overview
CVE-2024-7725 is a use-after-free vulnerability [CWE-416] in Foxit PDF Reader and Foxit PDF Editor on Windows. The flaw resides in the handling of AcroForms, where the application performs operations on objects without validating that they still exist in memory. Attackers can exploit this condition by crafting a malicious PDF document and convincing a user to open it or visit a malicious page. Successful exploitation results in arbitrary code execution in the context of the current process. The Zero Day Initiative tracked this issue as ZDI-CAN-23928 and published advisory ZDI-24-1127.
Critical Impact
Remote attackers can execute arbitrary code on systems running affected Foxit PDF Reader or Editor versions after a user opens a crafted PDF file.
Affected Products
- Foxit PDF Reader (Windows)
- Foxit PDF Editor (Windows)
- Versions referenced in the Foxit Security Bulletins
Discovery Timeline
- 2024-08-21 - CVE-2024-7725 published to NVD
- 2024-10-18 - Last updated in NVD database
Technical Details for CVE-2024-7725
Vulnerability Analysis
The vulnerability is a use-after-free condition in the AcroForms subsystem of Foxit PDF Reader and Foxit PDF Editor. AcroForms is the interactive form technology embedded within PDF documents, supporting JavaScript-driven form fields, calculations, and event handlers. When processing form content, the application operates on an object that has already been freed, leading to memory corruption.
An attacker can manipulate the freed memory region by controlling object allocations from JavaScript or form scripting. Once the dangling reference is dereferenced, the attacker gains control over function pointers or virtual table entries. This control path leads to arbitrary code execution within the process running Foxit PDF Reader.
User interaction is required: a victim must open a malicious PDF or visit a web page that delivers the document through the browser plug-in.
Root Cause
The root cause is the absence of an existence check before performing operations on an AcroForm object. The application retains a reference to an object whose backing memory has been released. Subsequent operations on that reference reuse the stale pointer, violating temporal memory safety.
Attack Vector
The attack vector is network-based with user interaction. An attacker hosts a malicious PDF on a web server, distributes it via email, or embeds it in a web page that triggers the browser plug-in. The exploitation chain proceeds:
- Victim opens the crafted PDF in Foxit PDF Reader or Editor.
- Embedded AcroForm scripting triggers the allocation and subsequent free of the target object.
- The application accesses the dangling reference.
- Attacker-controlled data placed in the reclaimed memory diverts execution.
- Shellcode executes in the context of the current user.
No synthetic exploit code is provided. Technical specifics are available in Zero Day Initiative Advisory ZDI-24-1127.
Detection Methods for CVE-2024-7725
Indicators of Compromise
- PDF files containing unusual AcroForm JavaScript that allocates and frees form field objects in tight sequences.
- Unexpected child processes spawned by FoxitPDFReader.exe or FoxitPDFEditor.exe, including cmd.exe, powershell.exe, or rundll32.exe.
- Outbound network connections initiated by the Foxit process shortly after opening a PDF.
- Crash dumps referencing AcroForm components with access violations on freed heap addresses.
Detection Strategies
- Inspect PDF documents at the email and web gateway for suspicious /AcroForm, /JavaScript, and /JS dictionary entries combined with heap-grooming patterns.
- Apply endpoint behavioral rules that flag process tree anomalies originating from Foxit binaries.
- Correlate file open telemetry with subsequent process creation and network activity to identify exploitation chains.
Monitoring Recommendations
- Monitor execution of FoxitPDFReader.exe and FoxitPDFEditor.exe for module loads from non-standard paths.
- Log AppLocker or Windows Defender Application Control events related to Foxit child processes.
- Track Application Event Log crashes for the Foxit binaries that reference faulting modules tied to AcroForm handling.
How to Mitigate CVE-2024-7725
Immediate Actions Required
- Update Foxit PDF Reader and Foxit PDF Editor to the latest version published on the Foxit Security Bulletins page.
- Inventory endpoints running Foxit products and prioritize patching for systems that process external PDFs.
- Block inbound PDF attachments from untrusted senders at the email gateway until patching is complete.
Patch Information
Foxit released fixed versions addressed in its security bulletin. Administrators should consult the Foxit Security Bulletins and apply the version that supersedes the vulnerable builds for both PDF Reader and PDF Editor on Windows.
Workarounds
- Disable JavaScript execution in Foxit PDF Reader and Editor through Preferences > JavaScript > Enable JavaScript Actions.
- Disable the browser plug-in to prevent automatic PDF rendering from web content.
- Configure Safe Reading Mode to restrict actions performed by untrusted PDF documents.
# Configuration example: registry key to disable JavaScript in Foxit PDF Reader
reg add "HKCU\Software\Foxit Software\Foxit PDF Reader\Preferences\JavaScript" /v bEnableJS /t REG_DWORD /d 0 /f
# Enable Safe Reading Mode
reg add "HKCU\Software\Foxit Software\Foxit PDF Reader\Preferences\TrustManager" /v bEnableSafeMode /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.
