CVE-2024-51321

Executive Summary

CVE-2024-51321 is an open redirect vulnerability in Zucchetti Ad Hoc Infinity version 2.4. The flaw resides in an improper check on the m_cURL parameter, allowing an attacker to redirect an authenticated user to an attacker-controlled website. This can be leveraged for phishing campaigns, credential harvesting, or as a vector for further social engineering attacks. The vulnerability has a CVSS score of 0.0 in the NVD but is assessed here with a more realistic vector. No official patch has been confirmed, and no public exploit code is available, but the attack vector is straightforward.

Supply Chain & Package Security

This vulnerability is not related to NPM, PyPI, Go, or Ruby packages. It is a web application vulnerability in a proprietary enterprise software product (Zucchetti Ad Hoc Infinity). The risk is primarily to organizations using this specific HR/payroll management platform.

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 (AV): Network – The vulnerability is exploitable remotely.
• Attack Complexity (AC): Low – No special conditions are required.
• Privileges Required (PR): None – The attacker does not need to be authenticated.
• User Interaction (UI): Required – The victim must click a crafted link.
• Scope (S): Changed – The redirect can impact resources beyond the vulnerable application.
• Confidentiality (C): Low – Potential for credential theft via phishing.
• Integrity (I): Low – The redirect can lead to a malicious site that may alter user data.
• Availability (A): None – No direct impact on availability.

Threat Level: Medium. While the CVSS is moderate, the lack of a patch and the simplicity of exploitation elevate the risk for organizations using this software.

Deep Dive & Mechanics

The vulnerability exists in the authentication flow of Zucchetti Ad Hoc Infinity 2.4. After a user successfully logs in, the application processes a m_cURL parameter to redirect the user to a specific page. The application fails to validate that the redirect target is within the same origin or a trusted domain. An attacker can craft a URL like:

https://vulnerable-ad-hoc-instance/login?m_cURL=https://attacker-controlled.com/phishing

When an authenticated user clicks this link (or is tricked into visiting it), the application will redirect the user's browser to the attacker's site. Since the user is already authenticated, the attacker can use this to steal session cookies, credentials, or deliver malware.

The root cause is a missing or insufficient validation of the m_cURL parameter. The application likely uses a function like redirect() or header("Location: ...") without checking if the URL is allowed.

Vulnerable vs. Patched Code

Vulnerable Code (Conceptual):

// Vulnerable: No validation of redirect URL
$redirect_url = $_GET['m_cURL'];
header("Location: " . $redirect_url);
exit();

Patched Code (Conceptual):

// Patched: Validate that the redirect URL is within the same domain
$redirect_url = $_GET['m_cURL'];
$allowed_hosts = ['example.com', 'sub.example.com'];
$parsed_url = parse_url($redirect_url);
if (in_array($parsed_url['host'], $allowed_hosts)) {
    header("Location: " . $redirect_url);
    exit();
} else {
    // Redirect to a default safe page
    header("Location: /dashboard");
    exit();
}

The patched version uses a whitelist of allowed hosts or checks that the URL is relative. Without an official patch, administrators must implement a reverse proxy rule or WAF rule to block open redirects.

Exploitation & Lab Setup

Red Team (Attack Simulation)

Lab Setup:

1. Deploy Zucchetti Ad Hoc Infinity 2.4 in a controlled environment.
2. Set up a simple HTTP server to capture redirected traffic (e.g., using Python: python3 -m http.server 8080).
3. Craft the exploit URL:

   http://victim-ad-hoc/login?m_cURL=http://attacker-server:8080/steal
   

4. Send the link to a test user (simulated via browser automation or manual click).
5. Observe the redirect in the attacker's server logs.

Exploit Code (Python):

import requests

target = "http://victim-ad-hoc/login"
attacker_site = "http://attacker-server:8080/steal"
exploit_url = f"{target}?m_cURL={attacker_site}"

print(f"Send this link to the victim: {exploit_url}")
# In a real scenario, the attacker would use phishing or social engineering.

Blue Team (Defense & Detection)

Detection:

• Monitor for unusual m_cURL parameters in web logs.
• Look for redirects to external domains after authentication.
• Use a WAF to block open redirect patterns.

Mitigation:

• Implement a reverse proxy (e.g., Nginx) to validate redirect URLs.
• Apply a Content Security Policy (CSP) with form-action and navigate-to directives.
• Restrict the m_cURL parameter to a whitelist of internal paths.

Indicators of Compromise (IOCs)

• URL Pattern: */login?m_cURL=* where the value is an external domain.
• Web Log Entries: HTTP 302 responses with Location header pointing to an external domain.
• Network Traffic: Outbound connections to unknown domains immediately after authentication.
• Phishing Pages: Copies of the Zucchetti login page hosted on attacker domains.

Detection Engineering

YARA Rule

rule CVE_2024_51321_Open_Redirect {
    meta:
        description = "Detects open redirect attempts targeting Zucchetti Ad Hoc Infinity"
        author = "Valters IT"
        date = "2024-01-01"
        reference = "CVE-2024-51321"
    strings:
        $redirect_param = "m_cURL="
        $external_domain = /https?:\/\/[^\/]+\.[^\/]+/
    condition:
        $redirect_param and $external_domain
}

Sigma Rule

title: Zucchetti Ad Hoc Infinity Open Redirect
id: 12345678-1234-1234-1234-123456789012
status: experimental
description: Detects open redirect attempts via m_cURL parameter
author: Valters IT
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-uri-query|contains: "m_cURL="
        sc-status: 302
        cs-uri-query|re: "https?://[^/]+\\.[^/]+"
    condition: selection
falsepositives:
    - Legitimate redirects to trusted external services (rare)
level: medium

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (
    msg:"CVE-2024-51321 Zucchetti Ad Hoc Infinity Open Redirect";
    flow:to_server,established;
    content:"m_cURL="; http_uri;
    pcre:"/https?:\/\/[^\/]+\.[^\/]+/";
    sid:1000001;
    rev:1;
)

Remediation & Mitigation

1. Immediate Action: If possible, disable the m_cURL parameter functionality or restrict it to a whitelist of internal paths.
2. WAF Rule: Deploy a Web Application Firewall rule to block requests where m_cURL contains an external domain.
3. Reverse Proxy: Use Nginx or Apache to validate redirect URLs before they reach the application.
4. User Awareness: Train users to recognize phishing links and avoid clicking suspicious URLs.
5. Vendor Contact: Reach out to Zucchetti for an official patch or workaround.
6. Monitor Logs: Actively monitor web logs for unusual redirect patterns.

Valters IT
Securing Digital Frontiers