Insufficient Logging in Echo Go with Mongodb

Insufficient logging in an Echo Go service that uses Mongodb can leave critical security events unrecorded, reducing the ability to detect or investigate incidents. When request and response payloads, authentication attempts, and database operations are not consistently logged, attackers can probe endpoints or manipulate data without leaving an audit trail.

In this combination, Echo handles HTTP routing and middleware, while Mongodb serves as the primary data store. If application code does not explicitly log key actions—such as authentication failures, authorization decisions, or database mutations—an incident may only be noticed after observable impact occurs (for example, unexpected data changes or service behavior). Without structured logs that include timestamps, user identifiers, request IDs, and operation outcomes, correlating events across layers becomes significantly harder.

The risk is especially relevant when endpoints accept user-supplied identifiers (e.g., userID, resourceID) that are directly used in Mongodb queries. Missing logs around query construction, filter application, and result handling can mask tampering or privilege escalation attempts. For example, an attacker may attempt to modify or access another user’s data via an Insecure Direct Object Reference (IDOR) pattern; if the service does not log the subject’s identity, the attempted access can go undetected.

Echo middleware provides a natural place to add request-scoped logging, but if developers omit structured entries for authentication outcomes, parameter validation, and database interactions, the service lacks visibility. Mongodb operations that fail due to validation or permissions should be recorded with sufficient context to support forensic analysis. Without this, organizations miss indicators of compromise such as repeated invalid tokens, malformed queries, or unusual filter patterns that could signal reconnaissance or exploitation.

To address this, ensure each significant step in an Echo Go + Mongodb flow is captured with consistent fields: timestamp, request ID, authenticated subject (or absence thereof), endpoint path, HTTP method, input parameters (sanitized), query filter, update specification, result status, and any error conditions. This approach aligns with the detection guidance found in assessments such as those run by middleBrick, which tests Authentication, BOLA/IDOR, Data Exposure, and other checks that rely on observable artifacts.

Remediation focuses on adding structured, informative logs at critical points in the Echo request lifecycle and around Mongodb interactions. Use a structured logger to ensure logs are machine-readable and support correlation across services. Below are targeted fixes and examples tailored to Echo Go and Mongodb.

• Log authentication and authorization outcomes with user context: Always record whether authentication succeeded or failed, and include the subject identifier when available. For unauthenticated requests, log the absence of a subject.
• Log database operations with query context: For each Mongodb operation, log the operation type, filter, update payload (sanitized), and result status. Include request IDs to tie logs to specific HTTP requests.
• Log input validation and sanitization steps: Record when incoming parameters fail validation and how they are transformed before being used in queries.

Example structured logger setup and usage in Echo Go with Mongodb:

import (
	"context"
	"fmt"
	"go.mongodb.org/mongo-driver/bson"
	"go.mongodb.org/mongo-driver/mongo"
	"go.mongodb.org/mongo-driver/mongo/options"
	"net/http"
	"strings"

	"github.com/labstack/echo/v4"
	"go.uber.org/zap"
)

type AuditLogger struct {
	logger *zap.Logger
}

func NewAuditLogger() *AuditLogger {
	l, _ := zap.NewProduction()
	return &AuditLogger{logger: l}
}

func (a *AuditLogger) RequestLog(next echo.HandlerFunc) echo.HandlerFunc {
	return func(c echo.Context) error {
		req := c.Request()
		// requestID should be set by a preceding middleware
		requestID := c.Get("requestID")
		a.logger.Info("http request started",
			zap.String("request_id", fmt.Sprintf("%v", requestID)),
			zap.String("method", req.Method),
			zap.String("path", req.URL.Path),
			zap.String("remote_addr", c.RealIP()),
		)
		return next(c)
	}
}

func SetupMongoWithLogging(client *mongo.Client, dbName string) *mongo.Collection {
	coll := client.Database(dbName).Collection("resources")
	return coll
}

func (a *AuditLogger) LogMongoOperation(op string, filter interface{}, update interface{}, requestID string, err error) {
	fields := []zap.Field{
		zap.String("request_id", requestID),
		zap.String("operation", op),
		zap.Any("filter", filter),
	}
	if update != nil {
		// Avoid logging sensitive or large update documents in full; sanitize if necessary
		fields = append(fields, zap.Any("update", update))
	}
	if err != nil {
		fields = append(fields, zap.String("error", err.Error()))
		a.logger.Warn("mongodb operation completed with error", fields...)
	} else {
		a.logger.Info("mongodb operation completed", fields...)
	}
}

// Example Echo handler with logging and safe query construction
func GetResourceHandler(coll *mongo.Collection, audit *AuditLogger) echo.HandlerFunc {
	return func(c echo.Context) error {
		requestID := c.Get("requestID").(string)
		userID := c.Param("userID")
		// Basic input validation
		if userID == "" {
			return c.String(http.StatusBadRequest, "missing user identifier")
		}
		// Construct filter safely; avoid direct string concatenation
		filter := bson.M{"_id": userID, "status": "active"}
		var result bson.M
		ctx := context.Background()
		err := coll.FindOne(ctx, filter).Decode(&result)
		audit.LogMongoOperation("find_one", filter, nil, requestID, err)
		if err != nil {
			if err == mongo.ErrNoDocuments {
				return c.String(http.StatusNotFound, "resource not found")
			}
			return c.String(http.StatusInternalServerError, "database error")
		}
		return c.JSON(http.StatusOK, result)
	}
}

// Example update handler with structured logging
func UpdateResourceHandler(coll *mongo.Collection, audit *AuditLogger) echo.HandlerFunc {
	return func(c echo.Context) error {
		requestID := c.Get("requestID").(string)
		userID := c.Param("userID")
		var payload struct {
			Status string `json:"status"`
			Role   string `json:"role"`
		}
		if err := c.Bind(&payload); err != nil {
			return c.String(http.StatusBadRequest, "invalid payload")
		}
		// Sanitize before logging if necessary
		update := bson.M{"$set": bson.M{"status": payload.Status, "role": payload.Role}}
		filter := bson.M{"_id": userID}
		res, err := coll.UpdateOne(c.Request().Context(), filter, update)
		audit.LogMongoOperation("update_one", filter, update, requestID, err)
		if err != nil {
			return c.String(http.StatusInternalServerError, "update failed")
		}
		if res.MatchedCount == 0 {
			return c.String(http.StatusNotFound, "resource not found")
		}
		return c.NoContent(http.StatusOK)
	}
}