Man In The Middle in Axum with Cockroachdb

A Man In The Middle (MitM) attack against an Axum service using CockroachDB can occur when communication between the application and the database is not strictly encrypted and authenticated. Axum, a web framework for Rust, typically handles HTTP requests and responses, and if it connects to CockroachDB over a plaintext or improperly validated TLS connection, an attacker on the network path can intercept or alter traffic. This risk is elevated in environments where TLS configuration is inconsistent, certificates are self-signed without proper verification, or the application fails to enforce strict certificate validation when opening a SQL connection.

CockroachDB supports secure connections via TLS, and the server can be configured to require client certificates. If Axum connects without enabling TLS or without validating the server certificate chain, an attacker who can position themselves between the service and the database (for example, within a shared network or a misconfigured Kubernetes pod network) can observe or modify SQL queries and results. This can lead to data exposure, unauthorized data modification, or session hijacking. In distributed deployments where nodes communicate across availability zones, missing encryption in-transit can turn a misconfigured node into a pivot point for broader lateral movement.

The combination of Axum’s runtime behavior and CockroachDB’s wire protocol can inadvertently expose sensitive information if retries or connection pooling are implemented without enforcing encryption. For example, an Axum application using a connection pool that reuses a non-TLS connection under certain conditions might open a window for interception. Because CockroachDB supports both internal and external traffic encryption, failing to explicitly require encryption for external connections increases the attack surface. Proper configuration and consistent use of secure endpoints are essential to prevent MitM in this stack.

To secure the Axum and CockroachDB connection, enforce TLS with strict certificate validation and avoid plaintext fallback. Below is a concrete Rust example using the sqlx crate with TLS enabled for CockroachDB. This ensures the client verifies the server certificate and establishes an encrypted channel.

use sqlx::postgres::PgConnectOptions;
use sqlx::ConnectOptions;
use std::time::Duration;

let mut options = PgConnectOptions::new()
    .host(&std::env::var("DB_HOST").unwrap_or_else(|_| "localhost".to_string()))
    .port(26257)
    .database(&std::env::var("DB_NAME").unwrap_or_else(|_| "defaultdb".to_string()))
    .username(&std::env::var("DB_USER").unwrap_or_else(|_| "root".to_string()))
    .password(&std::env::var("DB_PASSWORD").unwrap_or_else(|_| "".to_string()))
    .tls_mode(sqlx::postgres::PgTlsMode::Require)
    .connect_timeout(Duration::from_secs(10));

// Optional: provide a custom TLS connector with root certificates for stricter validation
// use sqlx::postgres::postgres_tls::MakeTlsConnector;
// use native_tls::TlsConnector;
// let tls = TlsConnector::builder().add_root_certificate(load_custom_root_cert()).build().unwrap();
// options = options.tls_connector(Box::new(tls));

let pool = sqlx::PgPool::connect_with(options).await.expect("Failed to connect to CockroachDB");

Additionally, configure CockroachDB server with enforced TLS and client certificate verification. A secure cockroach start command or configuration snippet ensures only encrypted client connections are accepted:

cockroach start --certs-dir=certs --host=your-host --port=26257 --advertise-host=internal --secure --tls-client-auth=require

Within Axum, ensure that any database interaction uses the established secure pool and that sensitive query results are handled with care to avoid logging or accidental exposure. Rotate certificates regularly and prefer HTTP Strict Transport Security (HSTS)-like policies at the infrastructure level to prevent downgrade attacks. These steps reduce the risk of interception and ensure that Axum communicates with CockroachDB over a verified, encrypted path.