From adcb5769760588c897c6b064042d1f60b5bde01b Mon Sep 17 00:00:00 2001
From: Tal Aloni <tal.aloni.il@gmail.com>
Date: Fri, 1 Sep 2017 18:53:42 +0300
Subject: [PATCH] NTLM: CHALLENGE_MESSAGE: Do not include TargetName and
 TargetInfo if the appropriate flags are not set

---
 .../NTLM/Structures/ChallengeMessage.cs               | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/SMBLibrary/Authentication/NTLM/Structures/ChallengeMessage.cs b/SMBLibrary/Authentication/NTLM/Structures/ChallengeMessage.cs
index 979a238..dd615b1 100644
--- a/SMBLibrary/Authentication/NTLM/Structures/ChallengeMessage.cs
+++ b/SMBLibrary/Authentication/NTLM/Structures/ChallengeMessage.cs
@@ -48,12 +48,21 @@ namespace SMBLibrary.Authentication.NTLM
 
         public byte[] GetBytes()
         {
+            if ((NegotiateFlags & NegotiateFlags.TargetNameSupplied) == 0)
+            {
+                TargetName = String.Empty;
+            }
+
+            if ((NegotiateFlags & NegotiateFlags.TargetInfo) == 0)
+            {
+                TargetInfo = new byte[0];
+            }
+
             int fixedLength = 48;
             if ((NegotiateFlags & NegotiateFlags.Version) > 0)
             {
                 fixedLength += 8;
             }
-
             int payloadLength = TargetName.Length * 2 + TargetInfo.Length;
             byte[] buffer = new byte[fixedLength + payloadLength];
             ByteWriter.WriteAnsiString(buffer, 0, AuthenticateMessage.ValidSignature, 8);