Re[2]: Authentication flaw in microsoft SMB protocol

[3APA3A <3APA3A () SECURITY NNOV RU>]

Dear Jesper Johansson,

This  attack  can  not  be  prevented  by  NTLMv2, because in a same way
attacker  can  relay  server's response. This kind of attack is possible
because  of pass-through authentication. This attack may be prevented by
SMB signing, which is available since SP3.

Kerberos  does  not  prevent  this  attack  too, because Kerberos is not
mandatory. Attacker can initiate NTLM with both client and server.

3APA3A. MCSE. MCT.

--Tuesday, April 22, 2003, 1:41:49 AM, you wrote to bugtraq () securityfocus com:


JJ> You don't need to wait. This is prevented with NTLM v.2, which shipped
JJ> with Windows NT 4.0 SP4 in October 1998. This type of attack is also
JJ> foiled with Kerberos, which is negotiated by default in a Windows 2000
JJ> or higher domain.

JJ> To learn more about using NTLM v.2 and Kerberos, refer to the Windows

JJ> Jesper M. Johansson
JJ> Security Program Manager
JJ> Microsoft Corporation


-- 
~/ZARAZA
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