CVE-2024-9247 Overview
CVE-2024-9247 is an out-of-bounds write vulnerability in Foxit PDF Reader and Foxit PDF Editor on Windows. The flaw resides in the handling of Annotation objects, where the application fails to properly validate user-supplied data. An attacker can trigger a write before the start of an allocated object, leading to memory corruption and arbitrary code execution in the context of the current process. Exploitation requires user interaction: the target must open a malicious PDF file or visit a page that serves crafted content. The issue was reported through the Trend Micro Zero Day Initiative as ZDI-CAN-24173 and published as advisory ZDI-24-1300.
Critical Impact
Successful exploitation allows attackers to execute arbitrary code with the privileges of the user running Foxit PDF Reader or Editor, enabling full compromise of the user context.
Affected Products
- Foxit PDF Reader for Windows
- Foxit PDF Editor for Windows
- Installations processing untrusted PDF documents containing crafted annotations
Discovery Timeline
- 2024-11-22 - CVE-2024-9247 published to the National Vulnerability Database
- 2026-06-17 - Last updated in the NVD database
Technical Details for CVE-2024-9247
Vulnerability Analysis
The vulnerability is classified as an out-of-bounds write [CWE-787] triggered during the parsing of Annotation objects inside a PDF document. Foxit PDF Reader accepts field values from the PDF structure without verifying that computed offsets fall within the bounds of an allocated buffer. When a crafted annotation is processed, the writer indexes to a location before the start of the target allocation and writes attacker-controlled data. This corrupts adjacent heap metadata or object structures, providing primitives that an attacker can chain into control-flow hijacking. Because the attack vector is local and requires user interaction, weaponization typically pairs the PDF with a social engineering lure delivered by email, chat, or a compromised website that renders the file in the browser plugin. Code executes at the privilege level of the interactive user, which on typical endpoints includes access to user data and persistence locations.
Root Cause
The root cause is missing input validation on values that influence pointer arithmetic during annotation handling. The Foxit code path calculates a destination address relative to an object base without confirming that the resulting pointer is not negative or below the allocation boundary. See the Zero Day Initiative advisory ZDI-24-1300 for the specific object type involved.
Attack Vector
An attacker crafts a PDF containing a malformed annotation and delivers it through email, download, or an inline browser render. When the target opens the file in a vulnerable version of Foxit PDF Reader or Editor, parsing of the annotation triggers the out-of-bounds write and executes attacker-supplied shellcode. No authentication is required, and no network access to the target is needed beyond delivery of the file.
No verified public proof-of-concept code is available. Refer to the Foxit Security Bulletins and the ZDI-24-1300 advisory for technical detail.
Detection Methods for CVE-2024-9247
Indicators of Compromise
- Unexpected child processes spawned by FoxitPDFReader.exe or FoxitPDFEditor.exe, particularly cmd.exe, powershell.exe, rundll32.exe, or wscript.exe.
- Crash events or Windows Error Reporting entries referencing the Foxit process with access violations at write operations.
- PDF files received from untrusted sources containing unusually structured annotation dictionaries.
Detection Strategies
- Hunt for anomalous process lineage where a PDF reader spawns interpreters, LOLBins, or network utilities.
- Monitor for outbound network connections initiated directly by the Foxit process shortly after a document open event.
- Inspect PDF attachments at the mail gateway for malformed annotation objects and abnormal object references.
Monitoring Recommendations
- Enable process creation logging (Windows Event ID 4688 or Sysmon Event ID 1) and centralize telemetry for endpoints running Foxit products.
- Alert on writes to autorun locations, scheduled task creation, and credential store access following a Foxit process start.
- Correlate Foxit crash telemetry with subsequent file, registry, and network activity on the same host.
How to Mitigate CVE-2024-9247
Immediate Actions Required
- Update Foxit PDF Reader and Foxit PDF Editor for Windows to the fixed versions listed in the Foxit Security Bulletins.
- Inventory all endpoints running Foxit products and prioritize patch deployment on systems that process external PDFs.
- Block or quarantine PDF attachments from untrusted senders at the email gateway until patching is complete.
Patch Information
Foxit has released updated versions of PDF Reader and PDF Editor that address the annotation handling flaw. Consult the Foxit Security Bulletins for the specific fixed builds and the Zero Day Initiative advisory ZDI-24-1300 for cross-reference. Apply the vendor update through the built-in updater or by deploying the latest installer via your endpoint management platform.
Workarounds
- Disable the Foxit browser plugin to prevent automatic rendering of PDFs served by websites.
- Configure Foxit Safe Reading Mode to restrict processing of untrusted content.
- Use Group Policy or application control to prevent Foxit PDF Reader from spawning child interpreters such as powershell.exe and cmd.exe.
- Route inbound PDFs through a content disarm and reconstruction (CDR) solution to strip active annotation content.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
