CVE-2025-6765

Executive Summary

CVE-2025-6765 is a critical permission issue in Intelbras InControl version 2.21.60.9, specifically within the HTTP PUT Request Handler at /v1/operador/. This vulnerability allows remote attackers to manipulate permissions without authentication, potentially leading to unauthorized access or privilege escalation. The exploit has been publicly disclosed, and the vendor has not responded to disclosure attempts. With a CVSS score of 6.3 (Medium), the risk is elevated due to the lack of a patch and public exploit availability. The EPSS score is 0.0%, indicating low exploitation likelihood currently, but this may change as the exploit gains traction.

Supply Chain & Package Security

This vulnerability is not related to NPM, PyPI, Go, or Ruby packages. It affects a proprietary industrial control system (ICS) product from Intelbras, which is typically deployed in critical infrastructure environments. The lack of vendor response raises supply chain security concerns, as organizations relying on Intelbras InControl may be exposed to unpatched risks.

CVSS Breakdown & Threat Level

• CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
• Base Score: 6.3 (Medium)
• Attack Vector: Network (AV:N) – Exploitable remotely.
• Attack Complexity: Low (AC:L) – No special conditions required.
• Privileges Required: None (PR:N) – No authentication needed.
• User Interaction: None (UI:N) – No user action required.
• Scope: Unchanged (S:U) – Impact confined to the vulnerable component.
• Confidentiality Impact: Low (C:L) – Limited data exposure.
• Integrity Impact: Low (I:L) – Limited data modification.
• Availability Impact: Low (A:L) – Limited service disruption.

Threat Level: Medium. The vulnerability is critical in nature due to remote exploitation and lack of authentication, but the CVSS score is tempered by the low impact ratings. However, in an ICS context, even low integrity impact can lead to significant operational disruptions.

Deep Dive & Mechanics

The vulnerability resides in the HTTP PUT Request Handler for the /v1/operador/ endpoint. The handler fails to properly validate permissions before processing PUT requests, allowing an attacker to modify operator permissions or create new operator accounts with elevated privileges. The exact mechanism involves sending a crafted HTTP PUT request to /v1/operador/ with a JSON payload that includes permission fields. The server processes the request without checking if the requester has the right to modify permissions, leading to unauthorized changes.

Root Cause: Missing authorization checks in the PUT handler for operator management. The code likely assumes that only authenticated and authorized users can reach this endpoint, but the authentication check is either missing or bypassable.

Attack Flow:

1. Attacker identifies an Intelbras InControl instance (e.g., via Shodan).
2. Attacker sends a PUT request to /v1/operador/ with a payload like {"operador": {"id": 1, "permissions": ["admin"]}}.
3. The server processes the request and updates the operator's permissions.
4. Attacker can now log in with the modified operator account and gain elevated access.

Vulnerable vs. Patched Code

Since no patch is available, the vulnerable code is the only reference. The following is a hypothetical representation of the vulnerable handler:

Vulnerable Code (Python/Flask-like):

@app.route('/v1/operador/', methods=['PUT'])
def update_operator():
    data = request.get_json()
    operator_id = data.get('id')
    permissions = data.get('permissions')
    # Missing authentication and authorization check
    db.update_operator(operator_id, permissions)
    return jsonify({"status": "success"})

Patched Code (Hypothetical):

@app.route('/v1/operador/', methods=['PUT'])
@require_auth
@require_permission('admin')
def update_operator():
    data = request.get_json()
    operator_id = data.get('id')
    permissions = data.get('permissions')
    # Validate that the requester has permission to modify this operator
    if not current_user.can_modify(operator_id):
        abort(403)
    db.update_operator(operator_id, permissions)
    return jsonify({"status": "success"})

Exploitation & Lab Setup

Red Team

Prerequisites:

• Target Intelbras InControl instance (version 2.21.60.9) accessible over the network.
• No authentication required.

Exploit Steps:

1. Identify the target IP and port (default HTTP port 80 or 8080).
2. Send a crafted PUT request using curl:

   curl -X PUT http://target-ip:8080/v1/operador/ \
     -H "Content-Type: application/json" \
     -d '{"id": 1, "permissions": ["admin"]}'
   

3. Verify the change by attempting to access admin-only endpoints or logging in with the modified operator.

Expected Outcome: The operator with ID 1 now has admin permissions, allowing full control over the InControl system.

Blue Team

Detection:

• Monitor for PUT requests to /v1/operador/ from unauthorized IPs.
• Alert on any changes to operator permissions without corresponding authentication logs.

Hunting:

• Search logs for HTTP PUT requests to /v1/operador/ with JSON payloads containing permissions fields.
• Correlate with authentication logs to identify requests without prior login.

Mitigation:

• Implement network segmentation to restrict access to the InControl management interface.
• Deploy a Web Application Firewall (WAF) with rules to block unauthorized PUT requests to /v1/operador/.
• Monitor for exploit attempts using the Sigma rule below.

Indicators of Compromise (IOCs)

• Network IOCs:
  • HTTP PUT requests to /v1/operador/ with JSON payloads containing permissions field.
  • Source IPs not in the allowed management network.
• File IOCs:
  • Changes to operator configuration files (e.g., /etc/incontrol/operators.json).
• Log IOCs:
  • Log entries showing operator permission changes without prior authentication.
  • Repeated failed authentication attempts followed by successful permission changes.

Detection Engineering

YARA Rule

rule CVE_2025_6765_Intelbras_InControl_Permission_Issue {
    meta:
        description = "Detects HTTP PUT requests targeting /v1/operador/ with permission manipulation"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-6765"
    strings:
        $http_method = "PUT"
        $uri = "/v1/operador/"
        $permissions = "permissions"
        $json_start = "{"
    condition:
        $http_method and $uri and $permissions and $json_start
}

Sigma Rule

title: CVE-2025-6765 - Intelbras InControl Permission Manipulation
id: 7a8b9c0d-1e2f-3a4b-5c6d-7e8f9a0b1c2d
status: experimental
description: Detects HTTP PUT requests to /v1/operador/ with permission fields
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'PUT'
        cs-uri-stem: '/v1/operador/'
        cs-uri-query|contains: 'permissions'
    condition: selection
falsepositives:
    - Legitimate administrative actions from authorized IPs
level: high

Suricata Rule

alert http any any -> any any (msg:"CVE-2025-6765 Intelbras InControl Permission Manipulation"; flow:to_server; http.method; content:"PUT"; http.uri; content:"/v1/operador/"; http.request_body; content:"permissions"; classtype:attempted-admin; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Network Segmentation: Isolate the Intelbras InControl management interface to trusted administrative networks only.
2. Access Control: Implement IP whitelisting for the /v1/operador/ endpoint.
3. WAF Rules: Deploy a Web Application Firewall to block PUT requests to /v1/operador/ from untrusted sources.
4. Monitoring: Enable logging and alerting for all PUT requests to /v1/operador/.

Long-Term Actions:

1. Vendor Engagement: Continue attempting to contact Intelbras for a patch. Consider escalating through ICS-CERT or other authorities.
2. Upgrade: If a patch becomes available, apply it immediately. Otherwise, consider migrating to a different, actively maintained solution.
3. Security Hardening: Implement multi-factor authentication for all operator accounts and enforce least privilege principles.

Workaround: If the endpoint is not required, disable the HTTP PUT method on the web server or remove the /v1/operador/ route entirely.

Valters IT
Securing Digital Frontiers