Technical Tip: Using FortiAnalyzer to detect activities related to the React2Shell Remote Code Execution | CVE-2025-55182 CVE-2025-66478

[emorlang_FTNT]

Description	This article describes how to use a custom event handler in FortiAnalyzer to raise alerts for incident response related to attacks that attempt to leverage the React2Shell Remote Code Execution. A report is also provided to gain historical visibility into the logs. Note that this article provides alpha files, which are automatically generated. The article will be continually updated as more information becomes available.
Scope	This article contains the files necessary to load an event handler and report into the FortiAnalyzer for either a Fabric ADOM or a FortiGate ADOM. The Fabric report and event handler leverage logs from other Fortinet products that can be used to detect the attack in addition to FortiGate logs. For more information about this attack, see the following FortiGuard Outbreak Alert: React2Shell Remote Code Execution
Solution	What is included in Fortinet_React2Shell Remote Code Execution.zip: React2Shell Remote Code Execution_event-handler.json: This event handler helps identify React2Shell Remote Code Execution attacks detected by FortiGate and other Fortinet products. This event handler is configured for Fabric ADOMs. React2Shell Remote Code Execution_report.dat: This report displays the findings on React2Shell Remote Code Execution attacks from FortiGate and other Fortinet products. It is configured for Fabric ADOMs. fgt_React2Shell Remote Code Execution_event-handler.json: The event handler for FortiGate ADOMs is configured for FortiGate logs only. fgt_React2Shell Remote Code Execution_report.dat: The FortiGate ADOMs report includes only FortiGate charts. Steps: Download the Fortinet_React2Shell Remote Code Execution.zip file (contains 4 files). Unzip Fortinet_React2Shell Remote Code Execution.zip. Import React2Shell Remote Code Execution_event-handler.json or fgt_React2Shell Remote Code Execution_event-handler.json event handler: Choose an ADOM (if ADOMs are enabled). The ADOM may have the Fabric or FortiGate type. Choose the FortiSOC module.  Select Event Handler List. Select the Import option under More. Select the appropriate event handler depending on the ADOM type. Result: The event handler is enabled and will be triggered if the appropriate logs are received following the import of the event handler.  Edit the event handler to customize the notification section. Import React2Shell Remote Code Execution_report.dat or fgt_React2Shell Remote Code Execution_report.dat to Reports: Choose an ADOM (if ADOMs are enabled). The ADOM may have the Fabric or FortiGate type. Choose the Report module. Select the Import option under 'More'. Select the appropriate file for the ADOM type to add the report to the ADOM. Result:  The React2Shell Remote Code Execution report can be run anytime, as determined by an admin user.