Arp Spoofing in Hanami with Cockroachdb

Arp Spoofing is a Layer 2 attack where an attacker sends falsified Address Resolution Protocol messages to associate their MAC address with the IP address of another host, typically the default gateway or another database server. In a Hanami application that uses Cockroachdb as its backend datastore, the risk is not that Arp Spoofing exploits a flaw in Hanami or Cockroachdb code, but that the network path between the Hanami process and the Cockroachdb cluster is manipulated. Cockroachdb often runs as a distributed cluster across multiple nodes, and Hanami applications typically connect to one or more of these nodes using a connection string that includes hostnames or IPs of Cockroachdb nodes. If an attacker on the same local network segment performs Arp Spoofing against the Hanami host or the Cockroachdb nodes, they can intercept or modify traffic intended for the database. Because Cockroachdb connections are usually long-lived and may carry sensitive data such as authentication tokens, user records, or session information, intercepted traffic can expose credentials or session data. Additionally, if the Hanami application connects to Cockroachdb without enforcing strict network segmentation, an attacker who successfully spoofs the MAC address of a Cockroachdb node could redirect queries, potentially injecting malicious statements or eavesdropping on query results. This attack surface is particularly relevant in environments where Hanami and Cockroachdb share the same local network, such as a Kubernetes cluster without proper network policies or a virtual private cloud with insufficient isolation.

The exposure is compounded by the nature of Cockroachdb’s wire protocol, which does not inherently encrypt traffic unless explicitly configured with TLS. Without TLS, ARP spoofing can facilitate man-in-the-middle attacks where the attacker observes or alters SQL commands issued by Hanami. Even if TLS is enabled, if certificate validation is not strictly enforced in the Hanami database configuration, an attacker could present a spoofed certificate and decrypt or modify traffic. Hanami applications that rely on environment variables or configuration files for database connection strings may inadvertently include hostnames that resolve to IPs vulnerable to ARP spoofing. Therefore, the combination of Hanami’s web-facing request handling and Cockroachdb’s distributed, multi-node architecture creates a scenario where local network attacks like ARP spoofing can lead to data exposure or integrity compromise if network-level protections are insufficient.

Remediation focuses on network architecture, transport security, and strict connection hygiene. First, ensure Hanami and Cockroachdb nodes are placed in isolated network segments with strict firewall rules that limit access to database ports (default 26257) only to Hanami application hosts. Avoid exposing Cockroachdb nodes directly on public networks. Second, enforce TLS for all Cockroachdb connections and configure Hanami to validate server certificates. Below is a concrete example of a Hanami application configuration that enforces TLS when connecting to Cockroachdb using the pg adapter, which is commonly used via the sequel gem.

require 'sequel'# Configure TLS for Cockroachdb connectionDB = Sequel.connect(  'postgres://username:password@cockroachdb-node1:26257,username:password@cockroachdb-node2:26257/dbname?sslmode=verify-full&sslrootcert=/path/to/ca.crt&sslcert=/path/to/client.crt&sslkey=/path/to/client.key',  max_connections: 10)

This connection string enforces full certificate verification (sslmode=verify-full), ensuring that Hanami only communicates with Cockroachdb nodes presenting certificates signed by the specified CA. The paths to the client certificate and key must be secured with appropriate file permissions. In a Hanami controller, avoid constructing dynamic queries that could be influenced by user input to prevent SQL injection, which could be leveraged in conjunction with a man-in-the-middle position. Additionally, use environment variables to inject sensitive parameters such as certificate paths and passwords, and rotate credentials regularly. For development, you can use Cockroachdb’s secure cluster setup command to generate certificates, but production deployments must automate certificate renewal and monitoring.