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Insecure functionality

Need​

Secure functionality implementation

Context​

  • Usage of Go 1.15 for building high-performance and scalable applications
  • Usage of gin-gonic/gin for building web applications and APIs in Go
  • Usage of net/http for creating a server and handling HTTP requests in a Node.js application

Description​

Non compliant code​

package main

import (
	"github.com/gin-gonic/gin"
	"net/http"
)

func main() {
	r := gin.Default()
	r.DELETE("/user/:id", deleteUser)
	r.Run()
}

func deleteUser(c *gin.Context) {
	id := c.Param("id")
	// Assume we have a function deleteUserFromDatabase(id string) that deletes a user from the database
	deleteUserFromDatabase(id)
	c.String(http.StatusOK, "User deleted")
}

The above code represents an insecure functionality vulnerability because it allows anyone to delete a user from the system. The DELETE endpoint /user/:id is open to all clients without any form of authentication or authorization. This means that an attacker can send a DELETE request to this endpoint with any user ID to delete the user associated with that ID.

The deleteUser function retrieves the user ID from the URL parameters and passes it to the deleteUserFromDatabase function (which is assumed to exist in this example). This function deletes the user from the database. After the user is deleted, a 200 OK response with the message "User deleted" is sent back to the client.

This is a serious vulnerability because it allows anyone to delete users from the system, potentially leading to data loss and unauthorized access to the system.

Steps​

  • Implement authentication and authorization mechanisms to ensure that only authorized users can access the deleteUser functionality.
  • Validate the user input to prevent any malicious input that could lead to unauthorized deletion of users.
  • Implement rate limiting or throttling mechanisms to prevent abuse of the deleteUser functionality.
  • Consider implementing a soft delete mechanism instead of directly deleting the user from the database, to allow for potential recovery or audit purposes.
  • Regularly update and patch the dependencies used in the application, including the gin framework, to ensure that any security vulnerabilities are addressed.
  • Perform regular security assessments and penetration testing to identify and address any other potential vulnerabilities in the application.

Compliant code​

package main

import (
	"github.com/gin-gonic/gin"
	"net/http"
	"github.com/dgrijalva/jwt-go"
	"time"
)

var SECRET_KEY = []byte("mySecretKey")

func main() {
	r := gin.Default()
	r.Use(AuthMiddleware())
	r.DELETE("/user/:id", deleteUser)
	r.Run()
}

func deleteUser(c *gin.Context) {
	id := c.Param("id")
	// Validate the id
	if id == "" {
		c.JSON(http.StatusBadRequest, gin.H{"error": "Invalid user ID"})
		return
	}
	// Assume we have a function deleteUserFromDatabase(id string) that deletes a user from the database
	deleteUserFromDatabase(id)
	c.String(http.StatusOK, "User deleted")
}

func AuthMiddleware() gin.HandlerFunc {
	return func(c *gin.Context) {
		tokenString := c.GetHeader("Authorization")
		token, err := jwt.Parse(tokenString, func(token *jwt.Token) (interface{}, error) {
			return SECRET_KEY, nil
		})

		if err != nil {
			c.JSON(http.StatusUnauthorized, "unauthorized")
			c.Abort()
			return
		}

		if claims, ok := token.Claims.(jwt.MapClaims); ok && token.Valid {
			c.Set("userId", claims["userId"])
		} else {
			c.JSON(http.StatusUnauthorized, "unauthorized")
			c.Abort()
			return
		}

		c.Next()
	}
}

The updated code includes an authentication middleware that uses JWT (JSON Web Tokens) for user authentication. The middleware function AuthMiddleware is used to authenticate the user before the deleteUser function is called.

The deleteUser function now also validates the user ID before proceeding with the deletion. If the ID is not valid, it returns a 400 Bad Request status code with an error message.

The AuthMiddleware function retrieves the token from the Authorization header of the request. It then parses and validates the token using the secret key. If the token is valid, it sets the user ID in the context and proceeds to the next handler. If the token is not valid, it returns a 401 Unauthorized status code and aborts the request.

This way, only authenticated users can access the deleteUser functionality, and the user input is validated to prevent any malicious input that could lead to unauthorized deletion of users.

Please note that this is a basic implementation of JWT authentication and you may need to adjust it according to your needs. For example, you might want to store the secret key in a more secure way, handle token expiration, or add more claims to the token.

Also, remember to implement rate limiting or throttling mechanisms to prevent abuse of the deleteUser functionality, consider implementing a soft delete mechanism instead of directly deleting the user from the database, regularly update and patch the dependencies used in the application, and perform regular security assessments and penetration testing.

References​

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