Jwt Misconfiguration in Echo Go with Cockroachdb

JWT misconfiguration in an Echo Go service backed by CockroachDB can expose authentication bypass or privilege escalation risks. When JWT validation is incomplete, an attacker can supply a token with a different algorithm (e.g., none or RS256 instead of the expected HS256) or manipulate claims such as roles or scopes. In Echo, if the middleware does not enforce strict algorithms and does not validate the issuer or audience, an attacker can craft a token that grants higher permissions or accesses other users’ data.

With CockroachDB as the data store, the risk amplifies because token claims often map to database rows (e.g., tenant_id or user_id). If the service decodes the JWT, extracts a user identifier, and directly interpolates it into SQL without strict authorization checks, attackers can exploit Insecure Direct Object References (IDOR) or Broken Object Level Authorization (BOLA). For example, changing a user_id claim or parameter to access another tenant’s rows in CockroachDB becomes possible when the application trusts the token without re-verifying context-specific authorization on each request.

A concrete scenario: an Echo route uses a JWT middleware that sets c.Set("user", claims), and a downstream handler builds a CockroachDB query like SELECT * FROM profiles WHERE user_id = $1 using a value extracted from claims. If the token’s user_id is not cross-checked against a server-side session or role mapping stored in CockroachDB, an attacker who obtains or guesses another user_id can read or modify that user’s data. Misconfigured token expiration or missing revocation checks can also allow reused or stolen tokens to have prolonged access to CockroachDB-backed resources.

To detect this during a scan, middleBrick checks whether the API exposes endpoints that accept or return tokens, whether JWT validation is strict (algorithm, issuer, audience, expiration), and whether authorization checks are repeated on the backend when accessing CockroachDB resources. Findings include missing algorithm enforcement, lack of token revocation, and unverified ID references to CockroachDB rows, each mapped to OWASP API Top 10 and relevant compliance frameworks.

Remediation centers on strict JWT validation and server-side authorization checks against CockroachDB. In Echo, configure the JWT middleware with explicit expected algorithms and claims validation, and ensure every CockroachDB query re-validates ownership and permissions.

// Example: strict JWT middleware and a protected handler
package main

import (
	"context"
	"net/http"

	"github.com/labstack/echo/v4"
	"github.com/labstack/echo/v4/middleware"
	"github.com/golang-jwt/jwt/v5"
)

type Claims struct {
	UserID string `json:"user_id"`
	Role   string `json:"role"`
	jwt.RegisteredClaims
}

func main() {
	e := echo.New()

	// Configure middleware with explicit expected signing method and issuer/audience
	e.Use(middleware.JWTWithConfig(middleware.JWTConfig{
		SigningMethod:   &middleware.SigningMethodHS256{},
		SigningKey:      []byte("your-256-bit-secret"),
		Claims:          &Claims{},
		ParseTokenFunc: func(tokenStr string) (interface{}, error) {
			// Reject unexpected signing methods
			token, err := jwt.ParseWithClaims(tokenStr, &Claims{}, func(token *jwt.Token) (interface{}, error) {
				if _, ok := token.Method.(*jwt.SigningMethodHMAC); !ok {
					return nil, http.ErrAbortNext
				}
				return []byte("your-256-bit-secret"), nil
			})
			if err != nil || token == nil || !token.Valid {
				return nil, http.ErrAbortNext
			}
			return token.Claims, nil
		},
	}))

	// Handler that re-validates ownership via CockroachDB
	e.GET("/profile/:id", func(c echo.Context) error {
		claims, ok := c.Get("user").(*Claims)
		if !ok {
			return echo.ErrUnauthorized
		}
		requestedID := c.Param("id")
		if claims.UserID != requestedID {
			return echo.ErrForbidden
		}

		// CockroachDB query with parameterized SQL and server-side ownership check
		ctx := c.Request().Context()
		conn, err := cockroachConnect()
		if err != nil {
			return echo.ErrInternalServerError
		}
		defer conn.Close()

		var profileOwner string
		row := conn.QueryRow(ctx, "SELECT user_id FROM profiles WHERE id = $1", requestedID)
		if err := row.Scan(&profileOwner); err != nil {
			return echo.ErrNotFound
		}
		if profileOwner != claims.UserID {
			return echo.ErrForbidden
		}
		// Safe to serve data
		return c.JSON(http.StatusOK, map[string]string{"profile": requestedID})
	})

	e.Logger.Fatal(e.Start(":8080"))
}

func cockroachConnect() (*cockroach.Conn, error) {
	// Example connection string for CockroachDB; use secure settings in production
	return cockroach.OpenDB(&cockroach.Driver{}, &cockroach.Options{
		Addresses: []string{"localhost:26257"},
		Database:  "apidb",
	})
}

Key remediation steps:

• Enforce a single signing method (e.g., HS256 or RS256 with a specific key) and reject unsigned tokens by customizing ParseTokenFunc.
• Validate standard claims: issuer (iss), audience (aud), and expiration (exp) within middleware or token parsing.
• In handlers, always re-check ownership against CockroachDB using parameterized queries; never trust path parameters or token claims alone for authorization.
• Use role or scope claims from the validated token to enforce least privilege; avoid broad or default roles.
• Implement short token lifetimes and a revocation mechanism (e.g., a denylist stored in CockroachDB) to limit the impact of leaked tokens.