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Account Takeover

Need​

Enhanced user authentication and authorization mechanisms

Context​

  • Usage of Go 1.16 for building efficient 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"
)

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

	r.POST("/login", func(c *gin.Context) {
		username := c.PostForm("username")
		password := c.PostForm("password")

		// Simulate a successful login
		if username == "admin" && password == "admin" {
			c.JSON(http.StatusOK, gin.H{
				"message": "Successfully logged in",
			})
		} else {
			c.JSON(http.StatusUnauthorized, gin.H{
				"message": "Unauthorized",
			})
		}
	})

	r.Run()
}

In the above code, we have a basic login endpoint implemented using the Gin framework in Go. When a POST request is made to the '/login' endpoint, the application retrieves the 'username' and 'password' fields from the form data, and checks if they match a hardcoded 'admin' username and password.

This code is vulnerable to an Account Takeover attack due to the following reasons:

  1. Hardcoded Credentials: The username and password are hardcoded into the application. Anyone who has access to the source code can easily gain access to the 'admin' account.

  2. No Account Lockout Mechanism: There is no mechanism to lock out an account after a certain number of failed login attempts. This allows an attacker to perform a brute force attack by trying different combinations of usernames and passwords until they find the correct one.

  3. No Password Hashing: The password is stored and compared in plain text. If an attacker is able to gain access to the system memory or intercept the network traffic, they can easily retrieve the password.

  4. No HTTPS: The application does not enforce the use of HTTPS. This means that the username and password are sent over the network in plain text, which can be intercepted by an attacker.

  5. No Session Management: The application does not manage user sessions. Once the attacker has the correct username and password, they can impersonate the user for as long as they want.

Steps​

  • Implement a secure authentication mechanism, such as using strong password hashing algorithms like bcrypt or Argon2.
  • Enforce a strong password policy, including minimum length, complexity requirements, and password expiration.
  • Implement account lockout mechanisms to prevent brute-force attacks.
  • Use secure session management techniques, such as using secure cookies with HttpOnly and Secure flags.
  • Implement multi-factor authentication (MFA) to add an extra layer of security.
  • Regularly update and patch the application and its dependencies to protect against known vulnerabilities.
  • Implement proper input validation and sanitization to prevent common web vulnerabilities like SQL injection and cross-site scripting (XSS).
  • Implement proper authorization checks to ensure that users can only perform actions they are authorized for.
  • Implement secure password reset functionality, including verifying the user's identity before allowing password changes.
  • Monitor and log authentication events to detect and respond to suspicious activities.
  • Regularly review and audit the codebase for security vulnerabilities and follow secure coding practices.

Compliant code​

package main

import (
	"github.com/gin-gonic/gin"
	"golang.org/x/crypto/bcrypt"
	"net/http"
)

var userStore = map[string]string{
	"admin": "$2a$10$N9qo8uLOickgx2ZMRZoHKuNpEg32/31C5OCYIHZc7gxDv8TTZ3yiG", // hashed password for "admin"
}

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

	r.POST("/login", func(c *gin.Context) {
		username := c.PostForm("username")
		password := c.PostForm("password")

		hashedPassword, ok := userStore[username]
		if !ok {
			c.JSON(http.StatusUnauthorized, gin.H{
				"message": "Unauthorized",
			})
			return
		}

		err := bcrypt.CompareHashAndPassword([]byte(hashedPassword), []byte(password))
		if err != nil {
			c.JSON(http.StatusUnauthorized, gin.H{
				"message": "Unauthorized",
			})
			return
		}

		c.JSON(http.StatusOK, gin.H{
			"message": "Successfully logged in",
		})
	})

	r.Run()
}

The updated code now uses the bcrypt password hashing algorithm to securely store and verify user passwords. This prevents attackers from being able to use stolen password hashes to impersonate users, as they would need to know the original password to generate the same hash.

In the main function, we define a userStore map that stores usernames and their corresponding hashed passwords. In a real application, this would be replaced with a secure database or other persistent storage mechanism.

In the /login route handler, we first check if the provided username exists in the userStore. If it doesn't, we return an "Unauthorized" response and stop processing the request.

Next, we use the bcrypt.CompareHashAndPassword function to compare the provided password with the stored hashed password. This function first hashes the provided password with the same salt used to generate the stored hash, then compares the two hashes. If they match, it means the provided password is correct.

If the password is incorrect, we return an "Unauthorized" response. If the password is correct, we return a "Successfully logged in" response.

This code is a basic example and does not include all the recommended security measures, such as account lockout mechanisms, secure session management, multi-factor authentication, input validation and sanitization, proper authorization checks, secure password reset functionality, and logging and monitoring. These should be implemented as appropriate for your specific application and threat model.

References​

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