Container Escape in Chi with Cockroachdb

A container escape in a Chi application using CockroachDB typically occurs when the application process running inside a container attains sufficient privileges to interact with the container runtime or host filesystem. This combination is notable because CockroachDB drivers and connection patterns in Chi services often run with broader filesystem access to support migrations, logging, or certificate mounts, which can be leveraged if input validation is insufficient.

Chi is a lightweight routing library for Go, and when endpoints accept parameters that influence CockroachDB operations (e.g., database or table names), improper validation may allow path traversal or command injection patterns that lead to container escape. For example, if an endpoint constructs CockroachDB connection arguments or SQL identifiers using unchecked user input, an attacker might inject sequences that read sensitive host files (such as /etc/hosts or /var/run/docker.sock) when the container runs with elevated capabilities.

During a middleBrick scan, unauthenticated checks examine how the API handles inputs that reach CockroachDB interactions, testing for BOLA/IDOR and Input Validation weaknesses. If the API exposes endpoints that dynamically reference CockroachDB nodes or databases without strict allowlists, an attacker could probe for container escape vectors that read host resources or manipulate mounted volumes. The scanner’s checks for Data Exposure and Unsafe Consumption are particularly relevant, as they detect whether responses inadvertently reveal paths or configurations that facilitate escape from the container boundary.

Real-world attack patterns include exploiting path traversal in file-serving handlers to reach Docker socket paths or abusing environment variables that CockroachDB clients read to form connection strings. OWASP API Top 10 A03:2023 (Injection) and A05:2021 (Broken Function Level Authorization) map closely to these risks, as malicious input can alter CockroachDB query behavior or escalate permissions.

middleBrick’s LLM/AI Security checks are relevant here because some Chi services use AI-assisted code generation to construct CockroachDB queries; if prompts leak or are injected, the resulting queries might expose container-level operations. The scanner tests for system prompt leakage and output PII, which could include database paths or container identifiers that aid an escape attempt.

Remediation focuses on strict input validation, avoiding dynamic database or table names, and ensuring CockroachDB client usage does not expose host paths. Below are concrete code examples for Chi that illustrate secure patterns.

1. Validate and restrict database/table identifiers

Never use raw user input to select databases or tables. Use an allowlist and map safe values to identifiers.

import (
  "github.com/go-chi/chi/v5"
  "regexp
)

func safeTableHandler(w http.ResponseWriter, r *http.Request) {
  table := chi.URLParam(r, "table")
  if !isValidTable(table) {
    http.Error(w, "invalid table", 400)
    return
  }
  query := fmt.Sprintf("SELECT * FROM mydb.public.%s", table) // safe: table validated
  // execute query with CockroachDB driver
}

func isValidTable(name string) bool {
  matched, _ := regexp.MatchString(`^[a-z_][a-z0-9_]{0,62}$`, name)
  allowed := map[string]bool{
    "users": true,
    "orders": true,
    "logs": true,
  }
  return allowed[matched]
}

2. Use parameterized queries and avoid dynamic SQL concatenation

Prevent injection by using placeholders for values and never concatenating identifiers.

import (
  "database/sql
  _ "github.com/lib/pq"
)

func getUser(w http.ResponseWriter, r *http.Request) {
  id := chi.URLParam(r, "id")
  var email string
  // CockroachDB placeholder usage
  err := db.QueryRow(r.Context(), "SELECT email FROM users WHERE id = $1", id).Scan(&email)
  if err != nil {
    http.Error(w, "not found", 404)
    return
  }
  // respond safely
}

3. Restrict filesystem access and avoid mounting sensitive paths

Ensure your container definitions do not mount the Docker socket or host proc. In your deployment manifests, avoid volumes like /var/run/docker.sock:/var/run/docker.sock. If your Chi app needs to read certs, mount a specific secret path rather than the entire host root.

# Example safe volume mount (not a full manifest)
volumes:
  - name: cockroach-certs
    secret:
      secretName: cockroach-certs
volumeMounts:
  - name: cockroach-certs
    mountPath: "/etc/certs"
    readOnly: true

4. Configure CockroachDB client with restricted permissions

When initializing the CockroachDB SQL client in Chi, avoid using the root user and prefer role-based access with minimal permissions.

import (
  "context"
  "database/sql"
  _ "github.com/lib/pq"
)

func newDB() (*sql.DB, error) {
  connStr := "postgresql://readonly_user:password@cockroachdb-host:26257/appdb?sslmode=require
  db, err := sql.Open("postgresql", connStr)
  if err != nil {
    return nil, err
  }
  return db, nil
}