Decrypting an 'Encrypted' password from ASP.NET 2.0 Membership

Question

I have a requirement to decrypt the Encrypted (not Hashed) passwords located in my aspnet_Membership table. In that database I see the Password (Encrypted) and PasswordSalt

Answer 1

Create a class that inherits from SqlMembershipProvider and in it you can call the decrypt.

All the code you need for this can be found in this article by Naveen Kohli:

After looking through the code in reflector, I saw that Microsoft providers decrypts in two steps. The encrypted password is actually a Base64 conversion of encrypted data. So first it converts it back from Base64 and then calls DecryptPassword method. I just did the easiest thing. Copied the code from Microsoft implementation, removed all the checks it was doing and then used it. Following class is an example of a class derived form SqlMembershipProvider with a method that just returns me password in clear text for a given encrypted password.

namespace MembershipPasswordRecover
{
    public class NetFourMembershipProvider : SqlMembershipProvider
    {
        public string GetClearTextPassword(string encryptedPwd)
        {
            byte[] encodedPassword = Convert.FromBase64String(encryptedPwd);
            byte[] bytes = this.DecryptPassword(encodedPassword);
            if (bytes == null)
            {
                return null;
            }
            return Encoding.Unicode.GetString(bytes, 0x10, bytes.Length - 0x10);

        }
    }
}

static void Main(string[] args)
{
    var passwordManager = new NetFourMembershipProvider();
    var clearPWd = passwordManager.GetClearTextPassword("encryptedpasswordhere");
    Console.WriteLine(clearPWd);
}