CVE-2024-53477: Jflyfox Jfinal CMS RCE Vulnerability

CVE-2024-53477 Overview

CVE-2024-53477 is a critical insecure deserialization vulnerability affecting JFinal CMS version 5.1.0. The vulnerability exists in the ApiForm.java file, where unauthorized deserialization of untrusted data can lead to arbitrary command execution on the affected system. Attackers exploiting this vulnerability can achieve full system compromise without requiring authentication.

Critical Impact

This insecure deserialization vulnerability allows unauthenticated remote attackers to execute arbitrary system commands on servers running JFinal CMS 5.1.0, potentially leading to complete server takeover, data exfiltration, and lateral movement within the network.

Affected Products

• JFinal CMS 5.1.0 (jflyfox:jfinal_cms)

Discovery Timeline

• 2024-12-02 - CVE-2024-53477 published to NVD
• 2025-11-25 - Last updated in NVD database

Technical Details for CVE-2024-53477

Vulnerability Analysis

This vulnerability is classified under CWE-502 (Deserialization of Untrusted Data). The flaw resides in the ApiForm.java component of JFinal CMS, which processes serialized Java objects without proper validation or sanitization. When the application deserializes attacker-controlled input, malicious objects can be instantiated, allowing arbitrary code execution in the context of the application server.

The vulnerability is exploitable over the network without requiring any authentication or user interaction. An attacker can craft a malicious serialized payload containing gadget chains that, when deserialized by the vulnerable component, trigger command execution. This attack pattern is common in Java applications that use native serialization mechanisms without implementing proper input validation or utilizing secure deserialization libraries.

Root Cause

The root cause of this vulnerability is the lack of input validation when deserializing data in the ApiForm.java file. The application accepts and processes serialized Java objects from untrusted sources without verifying the object types or implementing a whitelist of allowed classes. This allows attackers to inject malicious serialized objects containing dangerous class instantiations that execute arbitrary commands upon deserialization.

Attack Vector

The attack vector is network-based, requiring no privileges or user interaction. An attacker can send specially crafted HTTP requests containing malicious serialized payloads to the vulnerable API endpoint. The deserialization process automatically reconstructs the malicious objects, triggering the embedded command execution logic. Common exploitation techniques involve using known Java deserialization gadget chains from libraries present in the application's classpath.

The vulnerability mechanism involves sending a crafted serialized Java object to the vulnerable ApiForm.java endpoint. When the application deserializes this untrusted input, the malicious payload executes arbitrary system commands. For technical details and proof-of-concept information, refer to the GitHub Gist PoC.

Detection Methods for CVE-2024-53477

Indicators of Compromise

• Unusual HTTP requests to JFinal CMS API endpoints containing Base64-encoded or binary serialized Java data
• Unexpected child processes spawned by the Java application server (e.g., cmd.exe, /bin/sh, bash)
• Network connections to external command-and-control servers originating from the CMS application
• Suspicious entries in application logs indicating deserialization errors or unexpected class loading

Detection Strategies

• Deploy web application firewalls (WAF) with rules to detect and block serialized Java object patterns in HTTP requests
• Implement network intrusion detection signatures for known Java deserialization attack patterns
• Monitor JFinal CMS application logs for deserialization exceptions or unusual API requests
• Use endpoint detection and response (EDR) solutions to identify suspicious process chains originating from Java processes

Monitoring Recommendations

• Enable verbose logging on JFinal CMS to capture all API requests and responses
• Configure SIEM rules to alert on patterns consistent with deserialization exploitation attempts
• Monitor file system integrity on servers hosting JFinal CMS for unauthorized modifications
• Implement network traffic analysis to detect anomalous outbound connections from the application server

How to Mitigate CVE-2024-53477

Immediate Actions Required

• Take JFinal CMS 5.1.0 instances offline or restrict network access until a patch is applied
• Implement network segmentation to isolate affected CMS servers from critical infrastructure
• Deploy WAF rules to block potentially malicious serialized payloads
• Review server logs for evidence of exploitation attempts or successful compromise

Patch Information

As of the last update, users should monitor the official JFinal CMS GitHub repository for security updates. It is recommended to upgrade to the latest available version that addresses this vulnerability. Contact the vendor jflyfox for specific patching guidance and timeline information.

Workarounds

• Restrict access to the vulnerable API endpoints using firewall rules or authentication proxies
• Implement a Java serialization filter to whitelist only trusted classes during deserialization
• Consider using alternative serialization formats (JSON, XML) that do not execute code during parsing
• Deploy runtime application self-protection (RASP) solutions to detect and block deserialization attacks

If direct patching is not immediately possible, administrators can implement deserialization filters at the JVM level. Configure the jdk.serialFilter system property to restrict deserialization to only trusted classes. Additionally, ensure the application runs with minimal privileges to limit the impact of potential exploitation.