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Insecure encryption algorithm - SHA1

Need​

Implementation of secure encryption algorithms

Context​

  • Usage of Python 3 for scripting and application development
  • Usage of hashlib for cryptographic hashing operations

Description​

Non compliant code​

import hashlib

def encrypt_password(password):
    # Create a new SHA1 hash object
    sha1 = hashlib.sha1()

    # Update the hash object with the bytes of the password
    sha1.update(password.encode())

    # Get the hexadecimal representation of the hash
    return sha1.hexdigest()

In the above Python code, the function encrypt_password(password) is used to encrypt a password. This function uses the SHA1 hashing algorithm, which is considered insecure.

The function works as follows:

  1. A new SHA1 hash object is created using hashlib.sha1().
  2. The hash object is updated with the bytes of the password using sha1.update(password.encode()). Here, password.encode() converts the password string into bytes, as the update() method requires a bytes-like object.
  3. The hexadecimal representation of the hash is returned using sha1.hexdigest().

The vulnerability here is that SHA1 is not considered secure because it is susceptible to collision attacks. A collision occurs when two different inputs produce the same hash output. This means an attacker could potentially create a different password that produces the same hash as the user's actual password, thereby gaining unauthorized access.

Therefore, using SHA1 for password encryption in a Django backend application is a security risk and should be replaced with a more secure hashing algorithm, such as SHA256 or bcrypt.

Steps​

  • Replace the SHA1 hash function with a more secure hash function. SHA256, SHA3, or bcrypt are good alternatives.
  • Ensure that the new hash function is properly implemented in the 'encrypt_password' function.
  • Update the password encoding process to use the new hash function.
  • Test the updated function to ensure that it correctly hashes passwords.

Compliant code​

import hashlib

def encrypt_password(password):
    # Create a new SHA256 hash object
    sha256 = hashlib.sha256()

    # Update the hash object with the bytes of the password
    sha256.update(password.encode())

    # Get the hexadecimal representation of the hash
    return sha256.hexdigest()

The original code was using the SHA1 hash function to encrypt passwords. SHA1 is considered insecure because it is vulnerable to collision attacks, where two different inputs produce the same hash output. This makes it possible for an attacker to guess the original password.

The updated code uses the SHA256 hash function instead of SHA1. SHA256 is currently considered to be secure and is not vulnerable to collision attacks. The 'encrypt_password' function creates a new SHA256 hash object, updates the hash object with the bytes of the password, and then returns the hexadecimal representation of the hash.

This change improves the security of the password encryption process by using a more secure hash function. It's important to test the updated function to ensure that it correctly hashes passwords.

References​

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