Skip to main content

Incomplete funcional code

Need​

Ensuring complete and secure code implementation

Context​

  • Usage of Go 1.16 for developing high-performance and scalable applications
  • Usage of gin-gonic/gin for building web applications with Go
  • Usage of net/http for creating a server and handling HTTP requests in a Node.js application
  • Usage of io/ioutil for reading and writing files in Node.js

Description​

Non compliant code​

package main

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

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

	r.GET("/binary", func(c *gin.Context) {
		data, err := ioutil.ReadFile("sensitive_binary_file")
		if err != nil {
			c.JSON(http.StatusInternalServerError, gin.H{
				"message": "Unable to read binary file",
			})
			return
		}

		c.Data(http.StatusOK, "application/octet-stream", data)
	})

	r.Run()
}

The above code is a simple Go backend application using the Gin framework. It has a single route /binary that serves a binary file when accessed. The function ioutil.ReadFile is used to read the contents of the binary file named sensitive_binary_file.

The vulnerability lies in the fact that the binary file is served without any form of encryption or security measures. This means that any user who accesses this route will be able to download and potentially decompile the binary file, exposing any sensitive information stored within.

Additionally, the source code for creating this binary file is not present in the repository. This makes it difficult to verify the contents of the binary and ensure that it is not malicious or contains any vulnerabilities.

Steps​

  • Remove the sensitive binary file from the repository.
  • Ensure that the sensitive binary file is not included in future commits.
  • Encrypt the sensitive information stored in the binary file.
  • Store the encrypted sensitive information in a secure location, such as a database or a secure file storage system.
  • Modify the code to retrieve the encrypted sensitive information from the secure location and decrypt it before using it.
  • Implement access controls to restrict who can access the sensitive information.
  • Regularly monitor and update the encryption mechanism to ensure the security of the sensitive information.

Compliant code​

package main

import (
	"github.com/gin-gonic/gin"
	"net/http"
	"crypto/aes"
	"crypto/cipher"
	"encoding/base64"
	"io/ioutil"
	"log"
)

var key = []byte("my-32-byte-length-key!") // replace with your secure key

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

	r.GET("/binary", func(c *gin.Context) {
		encryptedData, err := ioutil.ReadFile("encrypted_sensitive_file")
		if err != nil {
			c.JSON(http.StatusInternalServerError, gin.H{
				"message": "Unable to read encrypted file",
			})
			return
		}

		data, err := decrypt(encryptedData, key)
		if err != nil {
			c.JSON(http.StatusInternalServerError, gin.H{
				"message": "Unable to decrypt file",
			})
			return
		}

		c.Data(http.StatusOK, "application/octet-stream", data)
	})

	r.Run()
}

func decrypt(ciphertext []byte, key []byte) ([]byte, error) {
	block, err := aes.NewCipher(key)
	if err != nil {
		return nil, err
	}

	if len(ciphertext) < aes.BlockSize {
		return nil, err
	}

	iv := ciphertext[:aes.BlockSize]
	ciphertext = ciphertext[aes.BlockSize:]

	stream := cipher.NewCFBDecrypter(block, iv)

	stream.XORKeyStream(ciphertext, ciphertext)

	return ciphertext, nil
}

The updated code now reads an encrypted file instead of a binary file. The encryption key is stored in the key variable. This key is used to decrypt the file content before sending it to the client.

The decrypt function is used to decrypt the encrypted file content. It uses the AES (Advanced Encryption Standard) algorithm for decryption. The initialization vector (IV) is extracted from the ciphertext and the ciphertext is decrypted using the cipher.NewCFBDecrypter function.

Please note that the encryption key should be stored securely and not be hardcoded as in this example. It's also important to handle the key securely to prevent it from being exposed.

The sensitive binary file has been removed from the repository and replaced with an encrypted file. This ensures that the sensitive information is not exposed even if the file is accessed.

Access controls should be implemented to restrict who can access the sensitive information. The encryption mechanism should be regularly monitored and updated to ensure the security of the sensitive information.

References​

Last updated on