CVE-2024-32409

Executive Summary

CVE-2024-32409 is a critical vulnerability in SEMCMS v4.8 that allows a remote attacker to execute arbitrary code via a crafted script. The vulnerability stems from insufficient input validation, enabling code injection. As of this report, no official patch has been released, and no public proof-of-concept (PoC) code is available. The EPSS score is 0.0%, indicating low exploitation activity in the wild, but the potential impact is severe.

Supply Chain & Package Security

This vulnerability is not related to NPM, PyPI, Go, or Ruby packages. It affects a standalone PHP-based CMS application.

CVSS Breakdown & Threat Level

The CVSS score is listed as 0.0, which is likely a placeholder. Based on the description and CWE-94 (Code Injection), the estimated CVSS v3.1 vector would be:

• Attack Vector (AV): Network (N)
• Attack Complexity (AC): Low (L)
• Privileges Required (PR): None (N)
• User Interaction (UI): None (N)
• Scope (S): Unchanged (U)
• Confidentiality (C): High (H)
• Integrity (I): High (H)
• Availability (A): High (H)

Estimated CVSS Score: 9.8 (Critical)

Deep Dive & Mechanics

The vulnerability in SEMCMS v4.8 is a code injection flaw (CWE-94). The application fails to properly sanitize user-supplied input before passing it to functions like eval(), assert(), or include(). An attacker can craft a malicious script (e.g., via a POST parameter, file upload, or URL parameter) that gets executed by the server.

Attack Vector:

1. The attacker identifies an input field (e.g., a search box, file upload, or configuration parameter) that is not sanitized.
2. The attacker injects PHP code, such as system('id'); or file_put_contents('shell.php', '<?php system($_GET["cmd"]); ?>');.
3. The injected code is executed by the PHP interpreter, allowing the attacker to run arbitrary commands on the server.

Potential Impact:

• Full remote code execution (RCE)
• Data exfiltration
• Server compromise
• Lateral movement within the network

Vulnerable vs. Patched Code

Since no official patch exists, the vulnerable code is the entire SEMCMS v4.8 codebase. The fix would involve:

• Vulnerable: Direct use of user input in dangerous functions.

  eval($_POST['code']);
  

• Patched: Proper input validation and sanitization.

  // Remove dangerous functions or use whitelisting
  $allowed_actions = ['view', 'edit', 'delete'];
  if (in_array($_POST['action'], $allowed_actions)) {
      // Safe execution
  } else {
      die('Invalid action');
  }
  

Exploitation & Lab Setup

Red Team (Exploitation)

Lab Setup:

1. Install SEMCMS v4.8 on a local server (e.g., XAMPP, LAMP).
2. Identify vulnerable endpoints (e.g., /admin/, /include/, etc.).
3. Use a web proxy (Burp Suite) to intercept and modify requests.

Exploitation Steps:

1. Send a crafted POST request to a vulnerable endpoint:

   POST /index.php HTTP/1.1
   Host: target.com
   Content-Type: application/x-www-form-urlencoded
   
   cmd=system('id');
   

2. Alternatively, upload a malicious PHP file via an insecure file upload function:

   <?php system($_GET['cmd']); ?>
   

3. Access the uploaded file to execute commands:

   GET /uploads/shell.php?cmd=id HTTP/1.1
   

Note: No public exploit code is available; this is a hypothetical scenario.

Blue Team (Defense)

Detection:

• Monitor for unusual POST parameters containing PHP code (e.g., system, exec, eval).
• Use WAF rules to block common PHP injection patterns.
• Enable detailed logging of all file uploads and code execution attempts.

Mitigation:

• Disable dangerous PHP functions (eval, assert, system, exec) in php.ini:

  disable_functions = eval, assert, system, exec, shell_exec, passthru, popen, proc_open
  

• Apply input validation and output encoding.
• Use a Web Application Firewall (WAF) with custom rules.

Indicators of Compromise (IOCs)

• Network:

  • POST requests containing PHP code in parameters (e.g., cmd=system('id')).
  • Unusual file uploads with .php extensions.
  • Outbound connections to unknown IPs after exploitation.

• Host:

  • Unexpected files in web directories (e.g., shell.php, cmd.php).
  • Modified .htaccess files.
  • Suspicious entries in web server logs (e.g., eval(base64_decode(...))).

• File Hashes (Example):

  • shell.php: e99a18c428cb38d5f260853678922e03 (MD5)

Detection Engineering

YARA Rule

rule CVE_2024_32409_SEMCMS_RCE {
    meta:
        description = "Detects PHP code injection attempts targeting SEMCMS v4.8"
        author = "Valters IT"
        date = "2025-04-01"
        reference = "CVE-2024-32409"
    strings:
        $php_func1 = /(eval|assert|system|exec|shell_exec|passthru|popen|proc_open)\s*\(/ nocase
        $php_func2 = /base64_decode\s*\(/ nocase
        $php_tag = "<?php"
        $post_param = /cmd|code|exec|action/
    condition:
        any of ($php_func*) and $php_tag and $post_param
}

Sigma Rule

title: CVE-2024-32409 SEMCMS RCE Attempt
id: 12345678-1234-1234-1234-123456789012
status: experimental
description: Detects HTTP POST requests with PHP code injection patterns targeting SEMCMS
author: Valters IT
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'POST'
        cs-uri-query|contains: 
            - 'cmd='
            - 'code='
            - 'exec='
        cs-uri-query|re: '(eval|system|exec|shell_exec|passthru|popen|proc_open)\s*\('
    condition: selection
falsepositives:
    - Legitimate administrative actions
level: high

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (
    msg:"CVE-2024-32409 SEMCMS RCE Attempt";
    flow:to_server,established;
    content:"POST"; http_method;
    content:"cmd="; http_client_body;
    pcre:"/(eval|system|exec|shell_exec|passthru|popen|proc_open)\s*\(/Pi";
    sid:1000001;
    rev:1;
    reference:cve,2024-32409;
    priority:1;
)

Remediation & Mitigation

1. Immediate Actions:

   • Disable dangerous PHP functions in php.ini.
   • Apply a WAF with custom rules to block injection attempts.
   • Restrict file uploads to only allowed extensions (e.g., .jpg, .png).

2. Long-term Fix:

   • Monitor the vendor for an official patch.
   • If no patch is released, consider migrating to a different CMS.
   • Conduct a full code audit of SEMCMS v4.8 to identify and fix all injection points.

3. Detection:

   • Deploy the YARA, Sigma, and Suricata rules provided above.
   • Enable detailed logging and alerting on suspicious POST requests.

Valters IT
Securing Digital Frontiers