NTLM Strong Hash generation

Src/DSInternals.Common.Test/Cryptography/NTHashTester.cs

@@ -70,5 +70,18 @@ namespace DSInternals.Common.Cryptography.Test
             string expected = "92937945B518814341DE3F726500D4FF";
             Assert.AreEqual(expected, result);
         }
+
+        [TestMethod]
+        public void NTHash_GenerateRandom()
+        {
+            byte[] randomHash1 = NTHash.GetRandom();
+            byte[] randomHash2 = NTHash.GetRandom();
+
+            // Check hash size
+            Assert.AreEqual(NTHash.HashSize, randomHash1.Length);
+
+            // Check that the hashes are not the same
+            Assert.AreNotEqual(randomHash1.ToHex(), randomHash2.ToHex());
+        }
     }
 }

Src/DSInternals.Common/Cryptography/NTHash.cs

@@ -2,6 +2,7 @@
 {
     using DSInternals.Common.Interop;
     using System.Security;
+    using System.Security.Cryptography;
 
     // See http://msdn.microsoft.com/en-us/library/system.security.cryptography.hashalgorithm%28v=vs.110%29.aspx
     public static class NTHash
@@ -45,5 +46,15 @@
             Validator.AssertSuccess(result);
             return hash;
         }
+
+        public static byte[] GetRandom()
+        {
+            using (var rng = RandomNumberGenerator.Create())
+            {
+                var randomHash = new byte[HashSize];
+                rng.GetBytes(randomHash);
+                return randomHash;
+            }
+        }
     }
 }

Src/DSInternals.Common/Interop/KerberosCryptoSystem.cs

@@ -10,27 +10,27 @@
     /// </summary>
     /// <remarks>This structure is undocumented. Kudos to Benjamin Delpy for figuring out the most important parts of it.</remarks>
     [StructLayout(LayoutKind.Sequential)]
-    internal struct KerberosCryptoSystem
+    internal class KerberosCryptoSystem
     {
-        internal KerberosKeyType Type;
-        int BlockSize;
-        KerberosKeyType Type1;
-        internal int KeySize;
-        int Size;
-        int Unknown2;
-        int Unknown3;
+        internal readonly KerberosKeyType Type;
+        readonly int BlockSize;
+        readonly KerberosKeyType Type1;
+        internal readonly int KeySize;
+        readonly int Size;
+        readonly int Unknown2;
+        readonly int Unknown3;
         [MarshalAs(UnmanagedType.LPWStr)]
-        internal string AlgorithmName;
-        IntPtr Initialize;
-        IntPtr Encrypt;
-        IntPtr Decrypt;
-        IntPtr Finish;
-        private KerberosKeyDerivationFunction KeyDerivationFunction;
-        IntPtr RandomKey;
-        IntPtr Control;
-        IntPtr Unknown4;
-        IntPtr Unknown5;
-        IntPtr Unknown6;
+        internal readonly string AlgorithmName;
+        readonly IntPtr Initialize;
+        readonly IntPtr Encrypt;
+        readonly IntPtr Decrypt;
+        readonly IntPtr Finish;
+        readonly KerberosKeyDerivationFunction KeyDerivationFunction;
+        readonly IntPtr RandomKey;
+        readonly IntPtr Control;
+        readonly IntPtr Unknown4;
+        readonly IntPtr Unknown5;
+        readonly IntPtr Unknown6;
 
         delegate NtStatus KerberosKeyDerivationFunction([In] ref SecureUnicodeString password, [In] ref UnicodeString salt, int iterations, [MarshalAs(UnmanagedType.LPArray), In, Out] byte[] key);
 

Src/DSInternals.Common/Interop/NativeMethods.cs

@@ -14,7 +14,6 @@ namespace DSInternals.Common.Interop
         internal const int LMHashNumBits = 128;
         internal const int LMHashNumBytes = NTHashNumBits / 8;
         internal const int LMPasswordMaxChars = 14;
-        // TODO: Validate NT Hash max chars
         internal const int NTPasswordMaxChars = 127;
 
         private const int MaxRegistryKeyClassSize = 256;
@@ -198,25 +197,7 @@ namespace DSInternals.Common.Interop
         }
 
         [DllImport(CryptDll, CharSet = CharSet.Auto, SetLastError = true)]
-        private static extern NtStatus CDLocateCSystem(KerberosKeyType type, out IntPtr cryptoSystem);
-
-        internal static NtStatus CDLocateCSystem(KerberosKeyType type, out KerberosCryptoSystem cryptoSystem)
-        {
-            IntPtr cryptoSystemPtr;
-            NtStatus status = CDLocateCSystem(type, out cryptoSystemPtr);
-
-            if(status == NtStatus.Success)
-            {
-                cryptoSystem = (KerberosCryptoSystem)Marshal.PtrToStructure(cryptoSystemPtr, typeof(KerberosCryptoSystem));
-            }
-            else
-            {
-                // Return a blank structure
-                cryptoSystem = new KerberosCryptoSystem();
-            }
-
-            return status;
-        }
+        internal static extern NtStatus CDLocateCSystem(KerberosKeyType type, out KerberosCryptoSystem cryptoSystem);
 
         /// <summary>
         /// Creates a subkey under HKEY_USERS or HKEY_LOCAL_MACHINE and loads the data from the specified registry hive into that subkey.