---
layout: docs
page_title: Consul NIA Security Model
sidebar_title: Network Infrastructure Automation <sup>Tech Preview</sup>
description: >-
  Security model including requirements, recommendations, and threats for Consul Network Infrastructure Automation (NIA). 
---

## Overview 

Consul Network Infrastructure Automation (NIA) enables declarative workflows to handle Day-2 network security
infrastructure tasks for network, security, and operations teams. NIA utilizes [Terraform](https://www.terraform.io/)
to propagate Consul catalog changes, and relevant configuration to network appliances, or network APIs.

### Personas

When thinking about Consul NIA, it helps to consider the following types of base personas when managing the security
requirements for the cluster deployment.

- **System Administrator** - This is someone who has access to the underlying infrastructure to the
  Consul NIA daemon, and possibly the core Consul service. Often she has access to SSH directly
  into a server within a cluster through a bastion host. Ultimately they have read, write and 
  execute permissions for the actual NIA daemon binary. These users potentially have sudo, 
  administrative, or some other super-user access to the underlying compute resource. Users like
  these are essentially totally trusted by Consul NIA as they have administrative rights to the 
  system and can start or stop the daemon.
  
- **Consul NIA Operator** - This is someone (probably the same System Administrator) who has access 
  to define the Consul NIA daemon configuration, and possibly a Consul ACL token, and other secrets to
  run the daemon against various network infrastructure APIs. They also have total rights to all of 
  the parts in the Consul NIA system including the ability to configure, start, and stop the daemon.

- **Developer** - This is someone who is responsible for creating, and possibly deploying applications
  connected, or configured with Consul. In some cases they may have no access, or limited capabilities 
  to view Consul information, such as through metrics, or logs.
  
- **User** - The end-user using the applications and other services managed by the NIA daemon, and should
  have no knowledge or access to the daemon’s API endpoints, ACL tokens, certificates, or any other 
  piece of the system.

### Secure Configuration

Consul NIA’s security model is applicable only if all parts of the system are running with a secure 
configuration; the daemon is not secure-by-default. Without the following mechanisms enabled in the 
daemon’s configuration, it may be possible to abuse access to the daemon. Like all security 
considerations, one must determine what concerns are appropriate for their environment, and adapt these
security concerns accordingly.

#### Requirements

- **Protect Configuration Files & Directories** - A dedicated NIA daemon user and group with limited 
  permissions should be created for production, along with directory and file permissions appropriately 
  scoped for your operating environment.

  Example commands to illustrate creating a dedicated `consul-nia` system user, along with the supporting 
  directories, configuration file, and securing those permissions using 
  [`chown`](https://en.wikipedia.org/wiki/Chown) and [`chmod`](https://en.wikipedia.org/wiki/Chmod):

  ```shell-session
  $ useradd --system --shell /bin/false consul-nia
  $ mkdir -p /consul-nia/data
  $ mkdir -p /consul-nia/config 
  $ echo "{ ... }" > /consul-nia/config/file.hcl
  $ chown --recursive consul-nia:consul-nia /consul-nia
  $ chmod -R 0750 consul-nia/
  ```

- **Protect Consul KV Path or Namespaces** - Note the NIA daemon can monitor Consul services in other Namespaces. 
  This can be limited based on the ACL token used for the NIA daemon. 

- **Use Consul ACLs** - The Access Control List (ACL) system within Consul can be used to restrict access to 
  only the required parts of Consul for the NIA daemon to operate.
  - **Read + Write** permission for Consul KV to the specified path, and namespace.
  - **Read** permission for Consul Catalog for all of the selected services to be monitored, and their namespaces.
  - **Read + Write** permission to update health checks, when using NIA health monitoring.

#### Recommendations

- **Use Dedicated Host** - The NIA daemon will potentially have access to critical secrets for your environment’s 
  network infrastructure. Using a hardened, dedicated host, for supporting these sensitive operations is highly. 
  Workload orchestrators, such as [HashiCorp Nomad](https://www.nomadproject.io/), also provide benefits of ensuring 
  uptime and isolation.

- **Run without Root** - The NIA daemon does not require root or other administrative privileges to operate. 

- **Protect NIA Daemon API Endpoint** - Any network endpoints provided by, or exposed to the NIA Daemon should be 
  protected using Consul Connect and appropriate firewall rules.

- **Use a centralized logging solution** - Export log entries within [syslog](https://en.wikipedia.org/wiki/Syslog) 
  generated from the NIA daemon to a centralized logging solution.

- **Audit used Terraform providers** - [Terraform providers](https://www.terraform.io/docs/providers/index.html) that 
  are configured with the NIA daemon should be audited to ensure you’re only using providers from sources that 
  you trust.

### Threat Model

The following are the parts of the NIA threat model:

- **Consul agent communication** - In order to monitor the Consul Catalog for changes, the NIA daemon interacts with 
  Consul’s HTTP API on a local or remote server agent. This communication requires TLS transport encryption, preferably
  using mTLS for mutual authentication.

- **NIA Terraform communication** - Network connectivity to downstream infrastructure APIs managed by the NIA daemon’s 
  Terraform runs will need to be properly configured for secure access.

- **Tampering of data in transit** - Any tampering should be detectable and cause the daemon to avoid processing the 
  request.

- **Access to data without authentication or authorization** - Requests to the Consul agent should be authenticated and 
  authorized using (m)TLS and ACLs respectively. ACLs should be configured with the minimal permissions required for 
  your environment.

- **Denial-of-Service** - DoS attacks against the NIA Daemon should not compromise the security of Consul, or Terraform,
  but may impact any networking components relying on updates from the daemon to properly handle traffic within the 
  network. Access to the daemon should be prevented using firewall rules.

The following are not a part of the threat model, as the NIA Daemon expects a secure configuration, while always 
providing the default options for testing in local environments which cannot be automatically configured to be both 
secure, and easily usable. However, these are valid concerns for Administrators and Operators to evaluate when hardening
a production deployment:

- **Access (read or write) to the Consul NIA Configuration Files or Directory** - Necessary configuration for the daemon
  process can be loaded from a single file or a directory of files. These configurations may contain secrets and can 
  enable/disable insecure features, or Terraform providers.

- **Access (read or write) to the Consul NIA Consul KV Path** - Access to the daemon’s Consul KV path may leak sensitive
  information such as usernames, passwords, certificates, and tokens used by Terraform to provision infrastructure.

- **Memory Access to a Running Consul NIA Daemon Process** - Direct access to the memory of running the daemon process 
  allows an attacker to extract sensitive information.

- **Memory Access to a Running Terraform Process** - Direct access to the memory of running the Terraform process 
  managed by the daemon process allows an attacker to extract sensitive information.

- **Access to the Terraform Binary** - Direct access to the Terraform binary used by the NIA daemon can allow an 
  attacker to extract sensitive information.

- **Access to the Consul NIA Daemon Binary** - Direct access to the system binary used to start the NIA daemon can allow
  an attacker to extract sensitive information.

#### Internal Threats

- **NIA Operator** - Someone with access to the NIA Host, and it’s related binaries or configuration files may be a 
  threat to your deployment, especially considering multi-team deployments. They may accidentally or intentionally use a 
  malicious Terraform provider, or extract various secrets to cause harm to the network. Access to the NIA host should 
  be guarded.

- **Consul Operator** - Someone with access to the backend Consul cluster, similar to the NIA Operator, which can 
  perform actions that may trigger Terraform runs. They may also have access to the namespace and KV path of the NIA
  daemon, which could give unintended access to Terraform’s state file, which contains sensitive information. ACL 
  permissions for Consul should be carefully audited to ensure that no policies may be leaking the state file containing
  sensitive information to other Consul operators unintentionally within the cluster.

- **System-bound Attackers** - Multi-tenant environments, especially container orchestrators, can introduce a number of 
  security concerns. These may include shared secrets, host volume access, and other sources of potential pivoting, or 
  privilege escalation from attackers with operating system-level access, or side-car container access, through various
  means. Extra steps to configuring OS, cluster, service, user, directory, and file permissions are essential steps for 
  implementing defense-in-depth within a production environment.

#### External Threats

- **Terraform Providers and Modules** - Potentially malicious providers or modules, or any malicious dependencies part 
  of the Terraform ecosystem could cause harm to the network, and may have access to secrets in order to make necessary
  network changes. Terraform provider configuration should be audited, pinned to a version, and audited for potential 
  typo-squatting issues from the Terraform Registry.

- **Network-bound Attackers** - Whenever a service is exposed to the open internet, which may be the case, you really 
  need to consider external network attackers which may seek-out hidden, unauthenticated, or otherwise vulnerable 
  endpoints. This can lead to larger security concerns when able to pivot to internal resources from an external one.

- **Leaking Secrets** - TLS certificates and tokens used by the Consul NIA daemon can enable external attackers to 
  access Consul, or Terraform resources. These secrets shouldn’t be hardcoded into configs uploaded to public 
  places like GitHub.