Business information leak - Users

Need

Protection of business information and user data confidentiality

Context

• Usage of Go 1.16 for building high-performance and scalable applications
• Usage of gin-gonic/gin for building web applications in Go
• Usage of net/http for handling HTTP requests and responses in a Node.js server

Description

Non compliant code

package main

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

type User struct {
	Name string `json:"name"`
	Email string `json:"email"`
}

var Users = []User{
	{Name: "John", Email: "[email protected]"},
	{Name: "Jane", Email: "[email protected]"},
}

func main() {
	r := gin.Default()

	r.GET("/users", func(c *gin.Context) {
		c.JSON(http.StatusOK, Users)
	})

	r.Run() // listen and serve on 0.0.0.0:8080
}

The code above is a simple Go web server using the Gin framework. It defines a list of users and exposes a GET endpoint /users which returns the list of all users when hit.

The vulnerability lies in the /users endpoint. This endpoint reveals the list of all users in the system, including their names and email addresses. This is sensitive information that should not be publicly accessible.

By simply sending a GET request to http://localhost:8080/users, an attacker can retrieve the list of all users, which is a serious business information leak vulnerability. This can lead to various attacks such as phishing, spamming, or even brute force attacks if the usernames are used for authentication.

To fix this vulnerability, you should ensure that this endpoint is either removed or protected with authentication and authorization mechanisms so that only authorized users can access it.

Steps

• Implement authentication and authorization mechanisms to restrict access to the /users endpoint.
• Ensure that only authenticated and authorized users can access the list of users.
• Use session management or token-based authentication to validate the user's identity.
• Implement role-based access control to limit access to sensitive information.
• Encrypt sensitive user information, such as email addresses, to protect them from unauthorized access.
• Regularly review and update access control policies to ensure they are effective and up to date.
• Implement logging and monitoring mechanisms to detect and respond to any unauthorized access attempts.

Compliant code

package main

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

type User struct {
	Name  string `json:"name"`
	Email string `json:"email"`
}

var Users = []User{
	{Name: "John", Email: "[email protected]"},
	{Name: "Jane", Email: "[email protected]"},
}

func main() {
	r := gin.Default()

	store := cookie.NewStore([]byte("secret"))
	r.Use(sessions.Sessions("mysession", store))

	r.GET("/login", func(c *gin.Context) {
		session := sessions.Default(c)
		session.Set("user", "authenticated")
		session.Save()
		c.String(http.StatusOK, "Logged in")
	})

	r.GET("/users", func(c *gin.Context) {
		session := sessions.Default(c)
		user := session.Get("user")
		if user == "authenticated" {
			c.JSON(http.StatusOK, Users)
		} else {
			c.JSON(http.StatusUnauthorized, gin.H{"error": "Unauthorized"})
		}
	})

	r.Run() // listen and serve on 0.0.0.0:8080
}

The updated code now includes an authentication mechanism using sessions. The /login endpoint sets a session variable user to authenticated. This session variable is then checked in the /users endpoint to ensure that only authenticated users can access the list of users.

The secret used in cookie.NewStore([]byte("secret")) should be replaced with a strong, unpredictable value that is kept secure, as it is used to encrypt the session data.

This is a simple example and in a real-world application, you would typically have a more secure authentication process, such as requiring a username and password to log in. You would also likely have more complex session management, such as expiring sessions after a certain period of inactivity.

Furthermore, this code does not yet include role-based access control or encryption of sensitive user information. These would be important additions for a production application. For example, you might encrypt email addresses before storing them and only decrypt them when necessary. You might also have different roles for users, such as 'admin' and 'user', and restrict access to certain endpoints based on these roles.

Finally, it's important to have logging and monitoring in place to detect any unauthorized access attempts. This could involve logging all requests to the application and setting up alerts for any suspicious activity.

References

• 221.Business information leak - Users