CVE-2025-8306

Executive Summary

CVE-2025-8306 is a critical access control vulnerability in Asseco InfoMedica, a comprehensive healthcare management solution. A low-privileged user can retrieve encoded passwords of all other accounts, including the main administrator, due to insufficient granularity in access control. This flaw, when chained with CVE-2025-8307, allows an attacker to escalate privileges to the highest level. The vulnerability has been patched in versions 4.50.1 and 5.38.0. No public proof-of-concept or exploit code is currently available, but the risk is high given the sensitive nature of healthcare data.

CVSS Breakdown & Threat Level

• CVSS Score: 0.0 (NVD assigned, likely due to incomplete data)
• Threat Level: Critical (based on impact and context)
• Attack Vector: Network (likely)
• Attack Complexity: Low
• Privileges Required: Low
• User Interaction: None
• Scope: Changed (due to privilege escalation)
• Confidentiality Impact: High (exposure of all passwords)
• Integrity Impact: High (potential for admin-level changes)
• Availability Impact: High (potential for denial of service or data destruction)

Deep Dive & Mechanics

The vulnerability stems from a lack of proper access control checks in the API or backend logic that handles user account data. A low-privileged user (e.g., a nurse or receptionist) can make a request to an endpoint that returns a list of all users and their encoded passwords. The encoding is likely a reversible transformation (e.g., Base64, simple XOR, or a weak hash) rather than a strong cryptographic hash, making it trivial to decode.

The chained exploitation with CVE-2025-8307 suggests that CVE-2025-8307 provides a mechanism to decode or use the obtained passwords, or to bypass additional authentication checks. The combined attack flow is:

1. Reconnaissance: Attacker gains low-privileged access (e.g., via phishing, weak credentials, or another vulnerability).
2. Exploitation of CVE-2025-8306: Attacker requests the user list endpoint and retrieves encoded passwords for all accounts, including the administrator.
3. Decoding: Attacker decodes the passwords (likely a simple transformation).
4. Privilege Escalation (CVE-2025-8307): Attacker uses the decoded admin credentials to log in and gain full administrative control.

Vulnerable vs. Patched Code

The vulnerable code likely resembles:

# Vulnerable endpoint (example)
@app.route('/api/users')
def get_users():
    # No privilege check
    users = db.query("SELECT username, encoded_password FROM users")
    return jsonify(users)

The patched code would include an authorization check:

# Patched endpoint (example)
@app.route('/api/users')
@require_role('admin')  # Only admins can list all users
def get_users():
    users = db.query("SELECT username, encoded_password FROM users")
    return jsonify(users)

The exact fix is proprietary, but the principle is to enforce role-based access control (RBAC) on the endpoint that exposes user credentials.

Exploitation & Lab Setup

Red Team (Offensive)

1. Setup: Deploy a vulnerable version of Asseco InfoMedica (e.g., 4.50.0) in a lab environment. Create a low-privileged user account (e.g., nurse1 with password nurse123).
2. Reconnaissance: Log in as nurse1 and explore the application's API endpoints. Look for endpoints that return user data, such as /api/users, /api/accounts, or /api/admin/users.
3. Exploitation: Send a GET request to the identified endpoint:

   GET /api/users HTTP/1.1
   Host: target-hospital.com
   Cookie: session=low_priv_session_token
   

4. Data Extraction: The response will contain a list of users and their encoded passwords. For example:

   [
     {"username": "admin", "encoded_password": "YWRtaW4xMjM="},
     {"username": "doctor1", "encoded_password": "ZG9jdG9yMTIz"}
   ]
   

5. Decoding: Decode the Base64 strings:

   echo "YWRtaW4xMjM=" | base64 -d
   # Output: admin123
   

6. Privilege Escalation: Log in as admin with the decoded password. Use CVE-2025-8307 if needed to bypass any additional checks.

Blue Team (Defensive)

1. Detection: Monitor for unusual API requests to user management endpoints from low-privileged accounts. Look for patterns like:
   • GET /api/users from non-admin users.
   • Multiple failed login attempts followed by a successful admin login from the same IP.
2. Hunting: Search logs for:
   • Requests to /api/users or similar endpoints.
   • Base64-encoded strings in HTTP responses.
   • Login events from admin account originating from unexpected IPs.
3. Mitigation: Immediately apply the patch (versions 4.50.1 or 5.38.0). If patching is not possible, implement a WAF rule to block access to user listing endpoints from non-admin IPs or roles.

Indicators of Compromise (IOCs)

• Network:
  • HTTP requests to /api/users, /api/accounts, or /api/admin/users from low-privileged user sessions.
  • Responses containing JSON arrays with encoded_password fields.
• Host:
  • Unusual login events for the admin account.
  • Presence of decoded password strings in memory or logs.
• Logs:
  • Application logs showing GET /api/users with a low-privileged role.
  • Authentication logs showing admin login from an unexpected IP address.

Detection Engineering

YARA Rule

rule CVE_2025_8306_Asseco_InfoMedica {
    meta:
        description = "Detects encoded passwords in Asseco InfoMedica responses"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-8306"
    strings:
        $encoded_pass = /"encoded_password"\s*:\s*"[A-Za-z0-9+/=]{10,}"/ 
        $user_list = /"username"\s*:\s*"[^"]+"/ 
    condition:
        all of them
}

Sigma Rule

title: Asseco InfoMedica User List Access by Low Privileged User
id: 8a4b3c2d-1e5f-4a7b-9c8d-0e1f2a3b4c5d
status: experimental
description: Detects attempts by low-privileged users to access the user list endpoint in Asseco InfoMedica.
author: Valters IT
date: 2025-04-10
references:
    - https://nvd.nist.gov/vuln/detail/CVE-2025-8306
logsource:
    category: application
    product: assec_infomedica
detection:
    selection:
        http_method: 'GET'
        url_path: '/api/users'
        user_role: 'low'
    condition: selection
falsepositives:
    - Legitimate admin access (should be filtered by role)
level: high

Suricata Rule

alert http any any -> any any (msg:"CVE-2025-8306 Asseco InfoMedica User List Access"; flow:to_server; http.method; content:"GET"; http.uri; content:"/api/users"; http.cookie; content:"session"; nocase; sid:1000001; rev:1;)

Remediation & Mitigation

1. Immediate Patch: Upgrade to Asseco InfoMedica version 4.50.1 or 5.38.0.
2. Workaround: If patching is delayed, implement a WAF rule to block access to /api/users and similar endpoints from non-admin IP addresses.
3. Access Control Review: Conduct a thorough review of all API endpoints to ensure proper role-based access control is enforced.
4. Password Policy: Enforce strong password hashing (e.g., bcrypt) and avoid reversible encoding for stored credentials.
5. Monitoring: Enable detailed logging for all user management API calls and set up alerts for suspicious access patterns.
6. User Training: Educate users about the risks of phishing and credential theft, as initial low-privileged access is required for exploitation.

Valters IT