If we use an Windows 7 or Vista client and a windows 2008 R2 server it will use NTLMv2. We can conclude that if we have an XP client and a windows 2008 R2 server with default settings it will always use NTLMv1. Now let’s take a look which values are used by default per OS type: So you’re actually configuring a minimum security level here. REG_DWORD Valuename: lmcompatibilitylevel HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Lsa This behavior can be changed on windows servers and clients at the following registry key: Thus we need to ensure that NTLMv2 only is allowed. There are many documents on the internet that show that LM and NTLMv1 are insecure these days therefore we need to ensure that these authentication methods are not allowed inside the windows network. This is very useful to know because it has a great impact on your security.
FOREFRONT TMG 2010 SMB2 HOW TO
This article will only show how to find out which SMB and NTLM versions are used on your windows servers and windows clients while using Wireshark. Step 6 – The server sends a success message embedded in an SMB_COM_SESSION_SETUP_ANDX response message. If the challenge and the response prove that the client knows the user’s password, the authentication succeeds and the client’s security context is now established on the server. Step 5 – The client extracts the ServerChallenge field from the NTLM CHALLENGE_MESSAGE and sends an NTLM AUTHENTICATE_MESSAGE to the server (embedded in an SMB_COM_SESSION_SETUP_ANDX request message).
The message includes an 8-byte random number, called a “challenge”, that the server generates and sends in the ServerChallenge field of the message. Step 4 – The server responds with an SMB_COM_SESSION_SETUP_ANDX response message within which an NTLM CHALLENGE_MESSAGE is embedded. Assuming that NTLM authentication is negotiated, within this message an NTLM NEGOTIATE_MESSAGE is embedded. Step 3 – The client sends an SMB_COM_SESSION_SETUP_ANDX request message. The following dialect values are possible (older dialects are excluded here): The client will send its supported dialects and the server will respond with the highest possible dialect. Step 1 and 2 – The SMB protocol negotiates protocol-specific options using the SMB_COM_NEGOTIATE request and response messages.
The following picture will show a protocol flow of NTLM and Simple and Protected Generic Security Service Application Program Interface Negotiation Mechanism (SPNEGO) authentication of an SMB session. For more in depth information I urge you to read this Microsoft NTLM documentation. In addition to authentication, the NTLM protocol optionally provides for session security-specifically message integrity and confidentiality through signing and sealing functions in NTLM. Each of these variants has three versions: LM, NTLMv1, and NTLMv2. There are two major variants of the NTLM authentication protocol: the connection-oriented variant and the connectionless variant.
NTLM is used by application protocols to authenticate remote users and, optionally, to provide session security when requested by the application. The NT LAN Manager (NTLM) Authentication Protocol is used in Microsoft Windows Networks for authentication between clients and servers. However, when a client attempts to authenticate to an SMB server using the KILE protocol and fails, it can attempt to authenticate with NTLM. Kerberos Protocol Extensions (KILE) is the preferred authentication method of an SMB session in Windows Server operating system and Windows Client operating systems. NTLM over a Server Message Block (SMB) transport is one of the most common uses of NTLM authentication and encryption. I noticed that our XP based network was running NTLMv1 that is considered unsecure. In this article I was looking at SMB and NTLM traffic in a windows environment. It has saved the day for me a couple of times by giving me information that is only retrieved by looking at packet level. The last few days I am playing around with wireshark and I must say I enjoy working with this program.
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