Implementation of DMARC (Domain-based Message Authentication, Reporting, and Conformance) records
package main
import (
"github.com/gin-gonic/gin"
"net/http"
)
func main() {
r := gin.Default()
r.POST("/sendEmail", func(c *gin.Context) {
var emailData EmailData
if err := c.ShouldBindJSON(&emailData); err != nil {
c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
return
}
sendEmail(emailData)
c.JSON(http.StatusOK, gin.H{"status": "Email sent"})
})
r.Run()
}
type EmailData struct {
From string `json:"from"`
To string `json:"to"`
Subject string `json:"subject"`
Body string `json:"body"`
}
func sendEmail(emailData EmailData) {
// Code for sending email
}
The above code is a simple email sending API endpoint using the Gin framework in Go.
When a POST request is made to the
/sendEmail endpoint, the
emailData object is parsed from the request body. This object contains the
From,
To,
Subject, and
Body of the email.
The parsed
emailData is then passed to the
sendEmail function, which handles the process of sending the email.
The vulnerability in this code lies in the fact that there is no verification of the
From field in the
emailData. This means that an attacker could potentially spoof the
From field, making it appear as if the email was sent from a different email address.
In addition, the absence of Domain-based Message Authentication, Reporting & Conformance (DMARC) records in the email sending process means that email receivers cannot verify whether the email was legitimately sent from the purported email domain. This could potentially allow an attacker to spoof the email domain, making it appear as if the email was sent from a different domain.
To fix this vulnerability, it is recommended to implement DMARC records in the email sending process to prevent email domain spoofing. Also, the
From field in the
emailData should be verified to ensure that it matches the authenticated user's email address.
package main
import (
"github.com/gin-gonic/gin"
"net/http"
"net/mail"
)
func main() {
r := gin.Default()
r.POST("/sendEmail", func(c *gin.Context) {
var emailData EmailData
if err := c.ShouldBindJSON(&emailData); err != nil {
c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
return
}
if err := validateEmail(emailData.From); err != nil {
c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
return
}
sendEmail(emailData)
c.JSON(http.StatusOK, gin.H{"status": "Email sent"})
})
r.Run()
}
type EmailData struct {
From string `json:"from"`
To string `json:"to"`
Subject string `json:"subject"`
Body string `json:"body"`
}
func validateEmail(email string) error {
_, err := mail.ParseAddress(email)
return err
}
func sendEmail(emailData EmailData) {
// Code for sending email
}
The updated code includes a function
validateEmail that validates the 'from' field of the email. This function uses the
mail.ParseAddress function from the Go standard library to parse the email address. If the email address is not valid, it returns an error.
In the main function, after binding the JSON data to the
emailData struct, it calls the
validateEmail function to validate the 'from' field of the email. If the email is not valid, it returns a 400 Bad Request status with an error message.
Please note that this code only validates the format of the email address. It does not authenticate the email address or prevent email spoofing. To prevent email spoofing, you should implement DMARC (Domain-based Message Authentication, Reporting, and Conformance) records for your email domain. You should also enable SPF (Sender Policy Framework) and DKIM (DomainKeys Identified Mail) to authenticate outgoing emails.
In addition, you should configure your DMARC policy to reject or quarantine emails that fail authentication. You should also consider implementing additional email security measures such as email encryption.
Finally, you should regularly update and patch the email sending library or service used in the 'sendEmail' function to address any security vulnerabilities.