Protection against Cross-Site Request Forgery (CSRF) attacks
package main
import (
"github.com/gin-gonic/gin"
)
func main() {
r := gin.Default()
r.POST("/changePassword", func(c *gin.Context) {
// Assume the user is authenticated
// Get the new password from the request body
newPassword := c.PostForm("newPassword")
// Change the user's password
// ...
c.JSON(200, gin.H{
"status": "Password changed successfully",
})
})
r.Run() // listen and serve on 0.0.0.0:8080
}
This is a simple Go backend application using the Gin framework. It has a single POST endpoint
/changePassword which accepts a new password from the request body and changes the user's password.
The vulnerability here is that there is no CSRF (Cross-Site Request Forgery) protection. If an authenticated user visits a malicious website, that website could send a POST request to
/changePassword without the user's knowledge or consent, effectively changing the user's password.
The application assumes that if a request is made to the
/changePassword endpoint, it must have come from an authenticated and authorized user. However, there are no checks in place to verify that the request was intentionally made by the user. This is the essence of a CSRF vulnerability.
To exploit this vulnerability, an attacker could create a website that sends a POST request to
/changePassword when visited. If an authenticated user visits this website, their password would be changed without their knowledge or consent.
package main
import (
"github.com/gin-gonic/gin"
"github.com/gin-contrib/sessions"
"github.com/gin-contrib/sessions/cookie"
)
func main() {
r := gin.Default()
store := cookie.NewStore([]byte("secret"))
r.Use(sessions.Sessions("mysession", store))
r.GET("/form", func(c *gin.Context) {
session := sessions.Default(c)
token := session.Get("csrf_token")
if token == nil {
token = generateCSRFToken() // function to generate a new token
session.Set("csrf_token", token)
session.Save()
}
c.HTML(200, "form.html", gin.H{"csrf_token": token})
})
r.POST("/changePassword", func(c *gin.Context) {
session := sessions.Default(c)
token := session.Get("csrf_token")
if token == nil || token != c.PostForm("csrf_token") {
c.JSON(403, gin.H{"message": "CSRF token mismatch"})
return
}
newPassword := c.PostForm("newPassword")
// Change the user's password
// ...
c.JSON(200, gin.H{
"status": "Password changed successfully",
})
})
r.Run() // listen and serve on 0.0.0.0:8080
}
func generateCSRFToken() string {
// Implement your CSRF token generation logic here
// This is just a placeholder
return "csrf_token"
}
The above code fixes the Cross-Site Request Forgery (CSRF) vulnerability in the Go application using the Gin framework.
The application now generates a CSRF token for each user session. This token is stored in the user's session and is also included as a hidden field in the HTML form that is used to change the password.
When the form is submitted, the server checks that the CSRF token in the form matches the CSRF token in the user's session. If the tokens do not match or if the token is missing, the server responds with a 403 Forbidden status code and does not process the request.
This prevents an attacker from tricking an authenticated user into executing actions without their consent, as the attacker would not have access to the CSRF token.
The application uses the
github.com/gin-contrib/sessions package to manage sessions and the
github.com/gin-contrib/sessions/cookie package to store session data in secure, encrypted cookies.
The
generateCSRFToken function is a placeholder and should be replaced with a function that generates a secure, random CSRF token.
The application also uses the POST HTTP method for the
/changePassword endpoint, which is a best practice for actions that modify sensitive data.
Finally, the application could further protect against CSRF attacks by implementing SameSite cookies, which are not included in cross-site requests.