CVE-2024-40873

Executive Summary

CVE-2024-40873 is a cross-site scripting (XSS) vulnerability in the Secure Access administrative console of Absolute Secure Access prior to version 13.07. An attacker with system administrator permissions can exploit this flaw to interfere with another administrator’s use of the publishing UI when both are editing the same management object. The vulnerability has a CVSS score of 4.5 (Medium), with high impact on integrity but no impact on confidentiality or availability. No public proof-of-concept (PoC) or exploit code is available at this time. The vendor has released a fix in version 13.07.

Supply Chain & Package Security

This vulnerability is not related to NPM, PyPI, Go, or Ruby packages. It affects a proprietary enterprise software product (Absolute Secure Access) and is not part of a public software supply chain.

CVSS Breakdown & Threat Level

• CVSS Score: 4.5 (Medium)
• Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:N/I:H/A:N
• Attack Vector: Network
• Attack Complexity: Low
• Privileges Required: High (system administrator)
• User Interaction: Required (another administrator must be editing the same object)
• Scope: Unchanged
• Confidentiality Impact: None
• Integrity Impact: High
• Availability Impact: None

The threat level is considered medium due to the requirement for high privileges and user interaction. However, the high integrity impact could allow an attacker to modify management objects, potentially leading to further compromise.

Deep Dive & Mechanics

The vulnerability exists in the Secure Access administrative console, specifically in the publishing UI. When two system administrators are editing the same management object (e.g., a policy or configuration), an attacker with administrator privileges can inject malicious JavaScript into the UI. This script executes in the context of the other administrator’s session, allowing the attacker to manipulate the object being edited.

The root cause is insufficient sanitization of user input in the publishing UI. The application fails to properly encode or validate data before rendering it in the browser, enabling stored XSS. Since the attacker already has administrative access, the primary risk is privilege escalation within the admin console or manipulation of critical configurations.

Vulnerable vs. Patched Code

Vulnerable Code (prior to 13.07):

// Example of vulnerable code that directly inserts user input into the DOM
function renderObjectName(name) {
    document.getElementById('objectName').innerHTML = name;
}

Patched Code (version 13.07):

// Patched code using textContent to prevent XSS
function renderObjectName(name) {
    document.getElementById('objectName').textContent = name;
}

The patch replaces innerHTML with textContent, which automatically escapes HTML entities and prevents script injection.

Exploitation & Lab Setup

Red Team

Prerequisites:

• Two administrator accounts with access to the Secure Access administrative console.
• The target administrator must be editing the same management object as the attacker.

Steps:

1. Log in as the attacker administrator.
2. Navigate to the publishing UI and select a management object (e.g., a policy).
3. In a field that is shared with other administrators (e.g., object name or description), inject the following payload:

   <img src=x onerror=alert('XSS')>
   

4. Save the changes.
5. When the victim administrator opens the same object for editing, the payload executes in their browser.

Expected Outcome: The attacker can execute arbitrary JavaScript in the victim’s session, allowing them to modify the object or steal session tokens.

Blue Team

Detection:

• Monitor for unusual JavaScript execution in the administrative console.
• Look for unexpected changes to management objects by administrators.
• Use web application firewalls (WAF) to block common XSS payloads.

Mitigation:

• Apply the vendor patch (upgrade to version 13.07).
• Implement strict input validation and output encoding.
• Enforce least privilege for administrator accounts.

Indicators of Compromise (IOCs)

• Network: HTTP requests containing XSS payloads (e.g., <script>, onerror=) to the Secure Access administrative console.
• Host: Unexpected JavaScript execution in browser developer tools.
• Logs: Multiple administrators editing the same object simultaneously; unusual changes to management objects.

Detection Engineering

YARA Rule

rule CVE_2024_40873_XSS {
    meta:
        description = "Detects XSS payloads targeting Absolute Secure Access admin console"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2024-40873"
    strings:
        $xss1 = /<script[^>]*>.*<\/script>/i
        $xss2 = /onerror\s*=\s*['"]?[^'"]*['"]?/i
        $xss3 = /onload\s*=\s*['"]?[^'"]*['"]?/i
    condition:
        any of them
}

Sigma Rule

title: CVE-2024-40873 XSS in Absolute Secure Access Admin Console
id: 12345678-1234-1234-1234-123456789012
status: experimental
description: Detects XSS payloads in HTTP requests to the Secure Access admin console
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'POST'
        cs-uri-query|contains:
            - '<script'
            - 'onerror='
            - 'onload='
    condition: selection
falsepositives:
    - Legitimate use of JavaScript in admin console (rare)
level: high

Suricata Rule

alert http any any -> any any (msg:"CVE-2024-40873 XSS in Absolute Secure Access Admin Console"; flow:to_server,established; content:"POST"; http_method; content:"/admin/"; http_uri; pcre:"/(<script|onerror=|onload=)/i"; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Upgrade Absolute Secure Access to version 13.07 or later.
2. Review administrator activity logs for signs of exploitation.
3. Implement web application firewall (WAF) rules to block XSS payloads.

Long-term Measures:

• Enforce strict input validation and output encoding in all web interfaces.
• Conduct regular security training for administrators.
• Implement multi-factor authentication (MFA) for admin accounts.

Workarounds:

• If patching is not immediately possible, restrict access to the administrative console to trusted IP addresses.
• Monitor for concurrent editing of management objects.

Valters IT