Email Injection in Chi with Cockroachdb

Email injection in a Chi application using Cockroachdb occurs when user-controlled input is concatenated into email-related commands or queries without proper validation or parameterization. Chi is a minimalistic HTTP router for Clojure that encourages explicit route handling; if developers build email headers or query strings by string concatenation, they can inadvertently allow an attacker to inject additional headers or commands.

When the application passes user input to a Cockroachdb instance, typically through a SQL driver, the lack of parameterized queries or input sanitization enables injection via crafted email fields. For example, an attacker might supply a payload such as [email protected]' OR '1'='1 in an email form field. If the application embeds this value directly into a SQL string, Cockroachdb may interpret the injected syntax as part of the query logic, altering its behavior.

Cockroachdb, while PostgreSQL-wire compatible, still adheres to SQL standards for literal quoting and escaping. In Chi, if SQL statements are built using string interpolation, a payload like ' ; DROP TABLE users; -- could modify the intended operation when combined with an email field. The vulnerability is not in Cockroachdb itself but in how the Chi application constructs queries. MiddleBrick scans detect such patterns by correlating unauthenticated endpoint testing with OpenAPI/Swagger spec analysis, highlighting places where email inputs reach the database layer without adequate safeguards.

Additionally, email headers constructed dynamically in Chi handlers can be susceptible to header injection if newline characters are not stripped. An attacker could provide a value like [email protected]\r\nCC: [email protected], causing the application to send unintended recipients. When these values are later stored or logged in Cockroachdb, the injected content persists, increasing exposure risk. MiddleBrick’s checks for Input Validation and Data Exposure help surface these weak points by analyzing runtime behavior against the declared spec.

Even with an OpenAPI spec that defines email formats, runtime deviations can occur if validation is lax. For instance, a spec may describe an email as a string with a pattern, but Chi routes might still pass raw parameters to Cockroachdb without enforcing those constraints. This mismatch between documentation and implementation is a common precursor to injection. MiddleBrick’s LLM/AI Security checks do not apply here, but its standard security checks evaluate whether input validation and property authorization are consistently enforced across endpoints that handle email data.

Developers should treat email fields as untrusted inputs, apply strict allow-lists for format, and use parameterized queries with the Cockroachdb driver. MiddleBrick can scan such endpoints without authentication, providing a security risk score and prioritized findings with remediation guidance to help teams address these specific chains of abuse.

To remediate email injection in Chi when interacting with Cockroachdb, adopt parameterized queries and strict input validation. Below are concrete code examples using the next.jdbc library, which is commonly used with Cockroachdb in Clojure/Chi projects.

1. Use parameterized SQL for any query involving email fields. Avoid string concatenation or interpolation.

(ns myapp.db
  (:require [next.jdbc :as jdbc]))

(def db {:dbtype "postgresql"
         :dbname "mydb"
         :host "my-cockroachdb-host"
         :port 26257
         :user "myuser"
         :password "mypassword"})

(defn find-user-by-email [email]
  (jdbc/execute! db ["SELECT id, email FROM users WHERE email = ?" email]))

2. Validate email format before using it in a query. Use a simple regex to enforce a basic pattern and reject inputs with newline characters that could enable header injection.

(ns myapp.validation
  (:require [clojure.string :as str]))

(defn valid-email? [email]
  (and (re-matches #"[^\s@]+@[^\s@]+\.[^\s@]+" email)
       (not (str/includes? email "\n"))
       (not (str/includes? email "\r"))))

3. In a Chi route, combine validation and parameterized queries to ensure only safe values reach Cockroachdb.

(ns myapp.handler
  (:require [chi.core :refer [GET POST route]])
  (:require [myapp.db :as db]
            [myapp.validation :as val]))

(route POST "/users" {:keys [body]}
  (let [email (:email body)]
    (if (val/valid-email? email)
      (do
        (db/find-user-by-email email)
        {:status 200 :body "OK"})
      {:status 400 :body "Invalid email"})))

4. For logging or storing email-related metadata, ensure that values are sanitized and that Cockroachdb receives only parameterized inputs. Avoid building dynamic SQL strings even for non-email fields.

These practices reduce the attack surface significantly. MiddleBrick can verify that endpoints applying such patterns show improved risk scores, and its GitHub Action can enforce checks in CI/CD pipelines, failing builds if insecure patterns are detected.