Distributed Denial Of Service in Chi with Cockroachdb

Chi is a functional, minimalist web framework for Clojure, and CockroachDB is a distributed SQL database that provides strong consistency across nodes. Using them together can expose DDoS risks when request handling and database interaction patterns amplify resource consumption. In Chi, unbounded or inefficient queries can cause prolonged database hold times, increasing connection pool saturation and backend load. Because CockroachDB is designed for distributed workloads, certain query behaviors—such as cross-node joins without proper indexes or fan-out transactions—can consume significant backend compute and network I/O. When Chi routes are not rate-limited or when retries are implemented without backpressure, the system can enter a feedback loop where pending queries accumulate, raising tail latencies and eventually exhausting thread or connection resources.

Unlike monolithic databases, CockroachDB’s consensus layer (Raft) adds coordination overhead. If Chi endpoints issue frequent write-heavy operations—such as upserts in loops or chatty transactions—across many nodes, the distributed commit process can become a bottleneck. Under high concurrency, this can manifest as latency spikes that resemble a DDoS condition for your own services: legitimate requests time out, retries multiply traffic, and node-level metrics show elevated Raft I/O. Moreover, if the API surface is unauthenticated or weakly guarded, an attacker can craft requests that trigger heavy distributed scans or range reads, indirectly starving capacity for legitimate traffic. MiddleBrick’s checks for Rate Limiting and Input Validation are relevant here because they surface missing guards that would otherwise allow query amplification or resource exhaustion in this stack.

Another vector specific to Chi + CockroachDB is improper handling of session or tenant context. If Chi applications construct SQL with naive string interpolation instead of parameterized statements, or fail to enforce row-level permissions, a single crafted request can trigger heavy distributed scans across ranges. Because CockroachDB exposes distribution metrics such as commit latency and leaseholder movement, an attacker can indirectly infer topology or drive cross-node traffic by targeting specific key ranges. The stack’s exposure is not just about raw requests per second; it’s about how query shape interacts with distribution, serialization, and backpressure mechanisms. MiddleBrick’s BOLA/IDOR and Data Exposure checks help identify endpoints where missing authorization or excessive data retrieval can turn logical bugs into effective denial-of-service triggers in this environment.

Defensive programming in Chi combined with disciplined SQL usage reduces DDoS risk. Use parameterized queries to avoid injection-driven heavy scans and ensure predicates leverage indexes to minimize distributed co-processing. Below is a concise example of a Chi handler that safely queries CockroachDB using next.jdbc with explicit prepared statements and bounded result sizes.

(ns example.handler
  (:require [chi.core :refer [defroutes GET POST]]
            [next.jdbc :as jdbc]
            [next.jdbc.result-set :as rs]))

(def db {:dbtype "cockroachdb"
         :dbname "mydb"
         :host "mycluster-free-tier.aivencloud.com"
         :port 26257
         :user "avnadmin"
         :password "..."
         :ssl {:ssl-mode "require"}})

(defn get-user-by-id [pool user-id]
  (jdbc/with-db-connection [conn pool]
    (jdbc/execute! conn
      ["SELECT id, username, email FROM users WHERE id = ? LIMIT 100" user-id]
      {:builder-fn rs/as-unqualified-lower-maps})))

(defroutes app-routes
  (GET "/users/:id" [id] ; id should be validated as integer or UUID
       (let [parsed-id (try (Long/parseLong id) (catch NumberFormatException _ nil))]
         (if (and parsed-id (pos? parsed-id))
           {:status 200 :body (get-user-by-id *db-pool* parsed-id)}
           {:status 400 :body {:error "invalid_id"}})))
  (POST "/search" [q] ; q should be length-bounded and sanitized
       (let [term (when q (subs q 0 (min (count q) 256)))]
         {:status 200
          :body (jdbc/with-db-connection [conn *db-pool*]
                  (jdbc/execute! conn
                    ["SELECT id, title FROM docs WHERE title ILIKE ? LIMIT 50" (str "%" term "%")]
                    {:builder-fn rs/as-unqualified-lower-maps}))})))

Key remediation practices for Chi + CockroachDB:

• Use prepared statements and parameterized queries to prevent injection-triggered heavy scans.
• Enforce strict input validation (length, type, format) at the Chi route level to avoid costly parsing or coercion.
• Set fetch/page limits on queries; avoid unbounded SELECT * or large IN lists that drive cross-node traffic.
• Enable request-level timeouts and context cancellation in Chi to prevent hung queries from exhausting connection pools.
• Monitor CockroachDB node metrics (Raft I/O, leaseholder movements) alongside Chi latency to detect amplification early.
• Apply middleware for rate limiting and concurrency caps; MiddleBrick’s Rate Limiting check can guide thresholds.