mirror of https://github.com/hashicorp/consul
125 lines
6.0 KiB
Markdown
125 lines
6.0 KiB
Markdown
---
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layout: docs
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page_title: Service Mesh Security - Best Practices
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description: >-
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Consul provides secure service mesh communication by default. Additional configuration can improve network security by preventing unauthorized access and traffic sniffing. Review security considerations, our recommendations, and best practices.
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---
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# Best Practices for Service Mesh Security
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Consul service mesh enables secure service-to-service communication over mutual TLS. This
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provides both in-transit data encryption as well as authorization. This page
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will document how to secure the service mesh. To try service mesh locally, complete the
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[Getting Started guide](/consul/tutorials/kubernetes-deploy/service-mesh?utm_source=docs) or for a full security model reference,
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see the dedicated [Consul security model](/consul/docs/security) page. When
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setting up service mesh in production, review this [tutorial](/consul/tutorials/developer-mesh/service-mesh-production-checklist?utm_source=consul.io&utm_medium=docs).
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Consul service mesh will function in any Consul configuration. However, unless the checklist
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below is satisfied, the service mesh is not providing the security guarantees it was
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built for. The checklist below can be incrementally adopted towards full
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security if you prefer to operate in less secure models initially.
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~> **Warning**: The checklist below should not be considered exhaustive. Please
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read and understand the [Consul security model](/consul/docs/security)
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in depth to assess whether your deployment satisfies the security requirements
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of Consul.
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## Checklist
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### Default Intention Policy Set
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Consul should be configured with a default deny intention policy. This forces
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all service-to-service communication to be explicitly
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allowed via an allow [intention](/consul/docs/connect/intentions).
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In the absence of `default_intention_policy` Consul will fall back to the ACL
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default policy when determining whether to allow or deny communications without
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an explicit intention.
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### ACLs Enabled with Default Deny
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Consul must be configured to use ACLs with a default deny policy. This forces
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all requests to have explicit anonymous access or provide an ACL token.
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To learn how to enable ACLs, please see the
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[tutorial on ACLs](/consul/tutorials/security/access-control-setup-production).
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**If ACLs are enabled but are in default allow mode**, then services will be
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able to communicate by default. Additionally, if a proper anonymous token
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is not configured, this may allow anyone to edit intentions. We do not recommend
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this. **If ACLs are not enabled**, deny intentions will still be enforced, but anyone
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may edit intentions. This renders the security of the created intentions
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effectively useless.
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### TCP and UDP Encryption Enabled
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TCP and UDP encryption must be enabled to prevent plaintext communication
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between Consul agents. At a minimum, `verify_outgoing` should be enabled
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to verify server authenticity with each server having a unique TLS certificate.
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`verify_incoming` provides additional agent verification, but doesn't directly
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affect service mesh since requests must also always contain a valid ACL token.
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Clients calling Consul APIs should be forced over encrypted connections.
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See the [Consul agent encryption page](/consul/docs/security/encryption) to
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learn more about configuring agent encryption.
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**If encryption is not enabled**, a malicious actor can sniff network
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traffic or perform a man-in-the-middle attack to steal ACL tokens, always
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authorize connections, etc.
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### Prevent Unauthorized Access to the Config and Data Directories
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The configuration and data directories of the Consul agent on both
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clients and servers should be protected from unauthorized access. This
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protection must be done outside of Consul via access control systems provided
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by your target operating system.
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The [full Consul security model](/consul/docs/security) explains the
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risk of unauthorized access for both client agents and server agents. In
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general, the blast radius of unauthorized access for client agent directories
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is much smaller than servers. However, both must be protected against
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unauthorized access.
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### Prevent Non-Mesh Traffic to Services
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For services that are using
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[proxies](/consul/docs/connect/proxies)
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(are not [natively integrated](/consul/docs/connect/native)),
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network access via their unencrypted listeners must be restricted
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to only the proxy. This requires at a minimum restricting the listener
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to bind to loopback only. More complex solutions may involve using
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network namespacing techniques provided by the underlying operating system.
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For scenarios where multiple services are running on the same machine
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without isolation, these services must all be trusted. We call this the
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**trusted multi-tenancy** deployment model. Any service could theoretically
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connect to any other service via the loopback listener, bypassing the service mesh
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completely. In this scenario, all services must be trusted _or_ isolation
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mechanisms must be used.
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For developer or operator access to a service, we recommend
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using a local service mesh proxy. This is documented in the
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[development and debugging guide](/consul/docs/connect/dev).
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**If non-proxy traffic can communicate with the service**, this traffic
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will not be encrypted or authorized via service mesh.
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### Restrict Access to Envoy's Administration Interface
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Envoy exposes an **unauthenticated**
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[administration interface](https://www.envoyproxy.io/docs/envoy/latest/operations/admin)
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that can be used to query and modify the proxy. This interface
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allows potentially sensitive information to be retrieved, such as:
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* Envoy configuration
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* TLS certificates
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* List of upstream services and endpoints
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We **strongly advise** only exposing the administration interface on a loopback
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address (default configuration) and restricting access to a subset of users.
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**If the administration interface is exposed externally**, for
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example by specifying a routable [`-admin-bind`](/consul/commands/connect/envoy#admin-bind)
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address, it may be possible for a malicious actor to gain access to Envoy's
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configuration, or impact the service's availability within the cluster.
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