Validator Security Checklist

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Conduct a security checklist survey to go through the security measures of a validator

Conduct Survey on General Controls of Hosting Data Centre

Perform a survey on the hosting data centre, and compare your result with the best practice suggested below

For example, your hosting data centre should have following features

Controls Category	Description of Best Practice
Data Center	Redundant Power
Data Center	Redundant Cooling
Data Center	Redundant Networking
Data Center	Physical Cage/Gated Access
Data Center	Remote Alerting Security Camera

Current Status of Node Setup

Perform a survey on your current status of node setup, and compare your result with the best practice suggested below

Controls Category	Description of Best Practice
General System Security	Operating system appropriately patched. Kernel is updated to latest stable version. The node should be operated in x86_64 environment
General System Security	Auto-updates for operation system is configured. Toolkit for automatic upgrades exists (e.g. auter, yum-cron, dnf-automatic, unattended-upgrades)
General System Security	Security framework enabled and enforcing. SELinux / AppArmor / Tomoyo / Grsecurity Enabled.
General System Security	No insecure and unnecessary services Installed. (e.g. telnet, rsh, inetd, etc ...)
General System Security	GRUB boot loader password is configured. Grub2 configured with password
General System Security	Only root permissions on core system files
File Directory Security	Secure the directory `~/.okp4d` to be accessible by owner only
Binary Configuration	Recommend the following settings in config.toml for both performance and security - For sentry nodes: `max_num_inbound_peers = 500, max_num_outbound_peers = 50, flush_throttle_timeout = "300ms"` - For validator node: `max_num_inbound_peers = 100, max_num_outbound_peers = 10, flush_throttle_timeout = "100ms"`
Account Security & Remote Access	Following Password policies are enforced: No Blank Passwords; Weak Passwords Not Allowed
Account Security & Remote Access	Following SSH configurations are enabled: PermitRootLogin: `no`; PasswordAuthentication `no`; ChallengeResponseAuthentication `no`; UsePAM `yes`; AllowUsers `Necessary user only`; AllowGroups `Necessary group only`.
Networking	Network throughput test using speedtest. Recommend to have at least 5 Mbps upload, 5 Mbps download)
Networking	Host-based (e.g. iptables) or cloud-based (e.g. AWS Security Group) firewall is enabled to protect all the involved nodes. Remote management ports (e.g. SSH - TCP 22) should only be exposed to selected IP instead of the internet. No overly permissive rules (e.g. wide range of allowed ports 1-65535) should be set. For internal communication channels between nodes, they should be set with specific source and destination addresses. For internet reachable nodes, set TCP 26656 to be the only incoming port, if possible.
Networking	Intrusion Detection / Prevention System (e.g. Fail2Ban, Snort, OSSEC) is installed and enforcing
Networking	Setup sentry node architecture to protect validator node, and set firewall rules to restrict direct internet access to it.
Networking	The Remote Procedure Call (RPC) provides sensitive operations and information that is not supposed to be exposed to the Internet. By default, RPC is on and allow connection from `127.0.0.1` only. Please be extremely careful if you need to allow RPC from other IP addresses.
Redundancy	Hot standby node is setup with the same configuration as main node
Redundancy	System monitoring and alerting is setup to alert owners on anomalies
Key Management	Setup Tendermint KMS with HSM or equivalent online service, which should replace the static key file.
DDOS	Setup validator in accordance with sentry architecture. Kindly refer to the setup instruction and detailed description.

Backup

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Learn how to backup your validator.

It is crucial to backup your validator's private key. It's the only way to restore your validator in the event of a disaster.

The validator private key is a Tendermint Key: a unique key used to sign consensus votes.

To backup everything you need to restore your validator, note that if you are using the "software sign" (the default signing method of Tendermint), your Tendermint key is located at:

~/.okp4d/config/priv_validator_key.json

To see your validator's associated public key:

okp4d tendermint show-validator

To see your validator's associated bech32 address:

okp4d tendermint show-address

You can also use hardware to store your Tendermint Key much more safely, such as YubiHSM2.

Alerting and monitoring

Alerting and monitoring is desirable as well - you are encouraged to explore solutions and find one that works for your setup. Prometheus is available out-of-the box, and there are a variety of open-source tools. Recommended reading:

Alerting:

Tenderduty: https://github.com/blockpane/tenderduty
PANIC: https://github.com/SimplyVC/panic_cosmos

Monitoring:

Simple setup using Grafana Cloud

Using only the raw metrics endpoint provided by okp4d you can get a working dashboard and alerting setup using Grafana Cloud. This means you don't have to run Grafana on the instance.

First, in config.toml enable Prometheus. The default metrics port will be 26660
Download Prometheus - this is needed to ship logs to Grafana Cloud.
Create a prometheus.yml file with your Grafana Cloud credentials in the Prometheus folder. You can get these via the Grafana UI. Click 'details' on the Prometheus card:

global:
  scrape_interval: 15s

scrape_configs:
  - job_name: cosmops
    static_configs:
    - targets: ['localhost:26660']
      labels:
        group: 'cosmops'

remote_write:
  - url: https://your-grafana-cloud-endpoint/api/prom/push
    basic_auth:
      username: ID_HERE
      password: "API KEY HERE"

3. Set up a service file, with sudo nano /etc/systemd/system/prometheus.service, replacing <your-user> and <prometheus-folder> with the location of Prometheus. This sets the Prometheus port to 6666

[Unit]
Description=prometheus
After=network-online.target

[Service]
User=<your-user>
ExecStart=/home/<your-user>/<prometheus-folder>/prometheus --config.file=/home/<your-user>/<prometheus-folder>/prometheus.yml --web.listen-address=:6666 --storage.tsdb.path=/home/<your-user>/<prometheus-folder>/data
Restart=always
RestartSec=3
LimitNOFILE=4096

[Install]
WantedBy=multi-user.target
/etc/systemd/system/prometheus.service

4. Enable and start the service.

sudo -S systemctl daemon-reload
sudo -S systemctl enable prometheus
sudo systemctl start prometheus

5. Import a dashboard to your Grafana. Search for 'Cosmos Validator' to find several options. You should see logs arriving in the dashboard after a couple of minutes.

For more info:

Sentry Nodes (DDOS Protection)

Validators are responsible for ensuring that the network can sustain denial of service attacks.

One recommended way to mitigate these risks is for validators to carefully structure their network topology in a so-called sentry node architecture.

Validator nodes should only connect to full-nodes they trust because they operate them themselves or are run by other validators they know socially. A validator node will typically run in a data center. Most data centers provide direct links the networks of major cloud providers. The validator can use those links to connect to sentry nodes in the cloud. This shifts the burden of denial-of-service from the validator's node directly to its sentry nodes, and may require new sentry nodes be spun up or activated to mitigate attacks on existing ones.

Sentry nodes can be quickly spun up or change their IP addresses. Because the links to the sentry nodes are in private IP space, an internet based attacked cannot disturb them directly. This will ensure validator block proposals and votes always make it to the rest of the network.

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Read more about Sentry Nodes on the forum

To setup your sentry node architecture you can follow the instructions below:

Validators nodes should edit their config.toml:

# Comma separated list of nodes to keep persistent connections to
# Do not add private peers to this list if you don't want them advertised
persistent_peers =[list of sentry nodes]

# Set true to enable the peer-exchange reactor
pex = false

Sentry Nodes should edit their config.toml:

# Comma separated list of peer IDs to keep private (will not be gossiped to other peers)
# Example ID: 3e16af0cead27979e1fc3dac57d03df3c7a77acc@3.87.179.235:26656

private_peer_ids = "node_ids_of_private_peers"

Conduct Survey on General Controls of Hosting Data Centre​

Current Status of Node Setup​

Backup​

Alerting and monitoring​

Simple setup using Grafana Cloud​

Sentry Nodes (DDOS Protection)​