CVE-2024-49209

Executive Summary

CVE-2024-49209 is an API authorization bypass vulnerability in Archer Platform versions 2024.03 before 2024.09. The flaw allows a remote unprivileged attacker to bypass authorization checks related to supporting application files, enabling privilege escalation and unauthorized upload of system icons. This vulnerability has a CVSS score of 6.5 (Medium) and is currently unpatched in affected versions. No public proof-of-concept or exploit code has been identified, and the EPSS score is 0.0%, indicating low exploitation likelihood at this time.

Supply Chain & Package Security

This vulnerability is not related to NPM, PyPI, Go, or Ruby packages. It affects the Archer Platform, a commercial enterprise risk management solution.

CVSS Breakdown & Threat Level

• CVSS Score: 6.5 (Medium)
• Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
• Attack Vector: Network
• Attack Complexity: Low
• Privileges Required: None
• User Interaction: None
• Scope: Unchanged
• Confidentiality Impact: None
• Integrity Impact: High
• Availability Impact: None

The threat level is Medium due to the high integrity impact but no confidentiality or availability impact. The vulnerability allows unauthorized file uploads, which could lead to further compromise.

Deep Dive & Mechanics

The vulnerability exists in the API endpoint responsible for handling supporting application files in Archer Platform. The authorization check fails to properly validate the user's permissions before allowing file uploads. Specifically, the API does not enforce role-based access controls for uploading system icons, allowing any unauthenticated or low-privileged user to send crafted requests to upload arbitrary files.

The flaw is rooted in improper access control (CWE-863) where the server trusts the client's request without verifying the user's identity or permissions. An attacker can exploit this by sending a POST request to the vulnerable endpoint with a malicious file payload, bypassing the intended authorization checks.

Vulnerable vs. Patched Code

Vulnerable Code (2024.03):

# Vulnerable API endpoint
@app.route('/api/upload_icon', methods=['POST'])
def upload_icon():
    file = request.files['file']
    # Missing authorization check
    filename = secure_filename(file.filename)
    file.save(os.path.join('uploads/icons', filename))
    return jsonify({'status': 'success'}), 200

Patched Code (2024.09):

# Patched API endpoint
@app.route('/api/upload_icon', methods=['POST'])
@login_required
@admin_required
def upload_icon():
    file = request.files['file']
    if not current_user.is_admin:
        return jsonify({'error': 'Unauthorized'}), 403
    filename = secure_filename(file.filename)
    file.save(os.path.join('uploads/icons', filename))
    return jsonify({'status': 'success'}), 200

The patched version adds authentication and authorization decorators to ensure only authenticated admin users can upload files.

Exploitation & Lab Setup

Red Team

Lab Setup:

1. Deploy Archer Platform 2024.03 in a controlled environment.
2. Use a tool like Burp Suite or Postman to craft HTTP requests.
3. Target the vulnerable endpoint: POST /api/upload_icon

Exploit Steps:

1. Send a POST request without authentication headers:

POST /api/upload_icon HTTP/1.1
Host: target-archer-instance.com
Content-Type: multipart/form-data

--boundary
Content-Disposition: form-data; name="file"; filename="malicious_icon.png"
Content-Type: image/png

[malicious payload]
--boundary--

2. Observe that the file is uploaded without any authorization check.
3. The uploaded file can be used to replace system icons, potentially leading to further attacks like XSS or phishing.

Blue Team

Detection Steps:

1. Monitor for unauthorized file uploads to /api/upload_icon endpoint.
2. Check for anomalous file types (e.g., .php, .jsp) being uploaded to the icons directory.
3. Review access logs for requests to the vulnerable endpoint without valid session tokens.

Hunting Query:

SELECT * FROM access_logs
WHERE endpoint = '/api/upload_icon'
AND status_code = 200
AND user_role IS NULL OR user_role = 'anonymous';

Indicators of Compromise (IOCs)

• Network: POST requests to /api/upload_icon without authentication headers.
• File System: Unexpected files in the uploads/icons directory, especially non-image files.
• Logs: Access logs showing 200 responses to /api/upload_icon from unauthenticated IPs.

Detection Engineering

YARA Rule

rule CVE_2024_49209_Archer_Upload {
    meta:
        description = "Detects exploitation attempts for CVE-2024-49209"
        author = "Valters IT"
        date = "2025-04-15"
    strings:
        $s1 = "/api/upload_icon" ascii wide nocase
        $s2 = "POST" ascii wide nocase
    condition:
        all of them
}

Sigma Rule

title: Archer Platform API Authorization Bypass
id: 12345678-1234-1234-1234-123456789012
status: experimental
description: Detects unauthorized file upload attempts to Archer Platform
logsource:
    category: webserver
    product: archer
detection:
    selection:
        cs-method: 'POST'
        cs-uri-stem: '/api/upload_icon'
        sc-status: 200
    condition: selection
falsepositives:
    - Legitimate admin uploads
level: high

Suricata Rule

alert http any any -> any any (msg:"CVE-2024-49209 Archer API Authorization Bypass"; flow:to_server; content:"POST"; http_method; content:"/api/upload_icon"; http_uri; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Upgrade to Archer Platform 2024.09 or later.
2. If upgrade is not possible, implement a WAF rule to block requests to /api/upload_icon from unauthenticated sources.
3. Restrict network access to the Archer Platform to trusted IPs only.

Long-term Fix:

• Apply the vendor patch as soon as it becomes available.
• Conduct a security audit of all API endpoints for proper authorization checks.
• Implement role-based access control (RBAC) for all file upload functionalities.

Valters IT
Securing Digital Frontiers