Nosql Injection in Echo Go with Basic Auth

Nosql Injection occurs when user-controlled input is interpreted as part of a NoSQL query without proper validation or parameterization. In Echo Go applications that rely on Basic Auth for access control, the combination of per-request authentication and unchecked query inputs can amplify the risk. When an endpoint accepts parameters such as username, password, or other identifiers and uses them to construct NoSQL queries (for example, in MongoDB or DynamoDB), unsanitized input can change query logic, bypass intended filters, or extract unintended data.

Consider an Echo Go handler that retrieves a user document from a MongoDB collection using values from the request context after Basic Auth has been validated. If the handler uses the authenticated username directly in a query map without sanitization, an attacker may manipulate the input to alter the query’s behavior. For instance, a username like {"username": {"$ne": null}} could be injected if the application does not enforce strict schema validation before building the query. This can lead to authentication bypass, unauthorized data access, or data exfiltration.

With Basic Auth, credentials are typically decoded from the Authorization header and may be used to scope or filter database lookups. If the application trusts these values implicitly—such as using the decoded username as a key in a NoSQL filter—there is a risk that crafted inputs can exploit NoSQL query operators. This is especially relevant when the API also exposes endpoints that accept additional query parameters that are merged into the same NoSQL query, creating a path for injection even though the initial authentication step appears intact.

middleBrick’s LLM/AI Security checks are unique in detecting prompt injection attempts, but its API security scans focus on traditional injection vectors like Nosql Injection across runtime and spec analysis. By scanning an unauthenticated attack surface, middleBrick can identify endpoints where NoSQL query construction relies on user-influenced data, even when Basic Auth is in place. This helps surface risky patterns such as unsanitized $in, $regex, or operator injection that could lead to privilege escalation or sensitive data exposure.

In practice, developers should treat values derived from authentication contexts as untrusted when building NoSQL queries. Validating against a strict schema, using parameterized queries or prepared statements where the driver supports them, and applying the principle of least privilege to database accounts are essential controls. middleBrick’s per-category breakdowns, mapped to frameworks such as OWASP API Top 10, can highlight these classes of findings and provide prioritized remediation guidance.

To reduce Nosql Injection risk in Echo Go services using Basic Auth, ensure that authentication-derived data is never used directly in query construction. Apply strict input validation, use parameterized queries, and isolate authentication context from database logic.

Below are concrete code examples demonstrating secure handling of Basic Auth in Echo Go.

• Secure Basic Auth parsing and validation

// Secure Basic Auth extraction and validation in Echo Go
func secureBasicAuthMiddleware(next echo.HandlerFunc) echo.HandlerFunc {
    return func(c echo.Context) error {
        auth := c.Request().Header.Get("Authorization")
        if auth == "" {
            return echo.NewHTTPError(http.StatusUnauthorized, "authorization header required")
        }
        const prefix = "Basic "
        if !strings.HasPrefix(auth, prefix) {
            return echo.NewHTTPError(http.StatusUnauthorized, "invalid authorization header")
        }
        payload, err := base64.StdEncoding.DecodeString(strings.TrimPrefix(auth, prefix))
        if err != nil {
            return echo.NewHTTPError(http.StatusUnauthorized, "invalid authorization encoding")
        }
        parts := strings.SplitN(string(payload), ":", 2)
        if len(parts) != 2 {
            return echo.NewHTTPError(http.StatusUnauthorized, "invalid credentials format")
        }
        username, password := parts[0], parts[1]
        if !isValidUsername(username) || !isValidPassword(password) {
            return echo.NewHTTPError(http.StatusUnauthorized, "invalid credentials")
        }
        // Store only verified, schema-compliant values in context
        c.Set("user", username)
        return next(c)
    }
}

func isValidUsername(username string) bool {
    // Enforce a strict pattern: alphanumeric with limited special characters
    matched, _ := regexp.MatchString(`^[a-zA-Z0-9._-]{3,64}$`, username)
    return matched
}

func isValidPassword(password string) bool {
    // Enforce a minimum length and complexity
    matched, _ := regexp.MatchString(`^.{8,128}$`, password)
    return matched
}

• Using parameterized queries to prevent Nosql Injection

// Example MongoDB query using validated, schema-bound values in Echo Go
func getUserProfile(c echo.Context) error {
    username := c.Get("user").(string)
    // Do NOT use raw user input in the filter; use validated, bounded values
    filter := bson.M{"username": username}
    var user User
    if err := usersCollection.FindOne(c.Request().Context(), filter).Decode(&user); err != nil {
        if errors.Is(err, mongo.ErrNoDocuments) {
            return echo.NewHTTPError(http.StatusNotFound, "user not found")
        }
        return echo.NewHTTPError(http.StatusInternalServerError, "database error")
    }
    return c.JSON(http.StatusOK, user)
}

• Avoiding dynamic query assembly

// Anti-pattern to avoid: building a filter from raw input
// This is unsafe and should not be used in production
func unsafeHandler(c echo.Context) error {
    var raw map[string]interface{}
    if err := c.Bind(&raw); err != nil {
        return echo.NewHTTPError(http.StatusBadRequest, "invalid body")
    }
    // UNSAFE: directly using user input in a NoSQL query
    filter := raw["filter"]
    var results []bson.M
    if err := usersCollection.Find(c.Request().Context(), filter).All(&results); err != nil {
        return echo.NewHTTPError(http.StatusInternalServerError, "database error")
    }
    return c.JSON(http.StatusOK, results)
}

By combining strict validation of Basic Auth credentials with parameterized queries and avoiding dynamic query assembly, you reduce the attack surface for Nosql Injection. middleBrick’s scans can verify that endpoints follow these patterns and highlight risky query construction practices.