C#


CSHARP.CRYPTO.SALT : Inadequate Salt (C#)

Summary

A cryptographic algorithm is used without a salt of sufficient size.

For more information see the Password Storage - OWASP Cheat Sheet Series.

Some cryptography algorithms are nowadays considered as outdated and unsafe or actually broken, since they are too easy to decode. This checker identifies uses of unsafe algorithms for cryptography.

Properties

Class Name Inadequate Salt (C#)
Significance security
Mnemonic CSHARP.CRYPTO.SALT
Categories
CWE CWE:916 Use of Password Hash With Insufficient Computational Effort
OWASP-2017 OWASP-2017:A2 Broken authentication
OWASP-2021 OWASP-2021:A7 Identification and authorization failures
Availability Available for C# only.
Enabling Checks for this warning class are disabled by default, and require strict C# analysis mode which is also disabled by default. To enable the checks, make the following changes to the project configuration file.
CSHARP_ANALYSIS_STRICT_MODE = Yes
WARNING_FILTER += allow class="Inadequate Salt (C#)"

Example

using System;
using System.Security.Cryptography;
using System.Text;

namespace DocumentationExample
{
    class OtherCryptographyExamples
    {

        static void Main(string[] args)
        {

            Console.WriteLine("Enter a password to produce a key:");

            byte[] pwd = Encoding.Unicode.GetBytes(Console.ReadLine());

            byte[] salt = new byte[6];

            RNGCryptoServiceProvider rand = new RNGCryptoServiceProvider();
            rand.GetBytes(salt);

            AesCryptoServiceProvider aes = new AesCryptoServiceProvider();

            try
            {

                PasswordDeriveBytes pdb = new PasswordDeriveBytes(pwd, salt); // Two warnings issued here: 
                                                                              // - Insecure Key Derivation (C#)
                                                                              //   because PasswordDeriveBytes() is deprecated in favor of Rfc2898DeriveBytes().
                                                                              // - Inadequate Salt (C#)
                                                                              //   because 'salt' is only 6 bytes.

                // Create the key and set it to the Key property
                // of the AesCryptoServiceProvider object.
                aes.Key = pdb.CryptDeriveKey("Aes", "SHA256", 192, aes.IV);

                // ...

            }
            catch (Exception e)
            {
                Console.WriteLine(e.Message);
            }

        }
       
    }
}

Resolution

Use a safer cryptography algorithm.

Relevant Configuration File Parameters

The following configuration file parameters affect checks for this warning class.