Bugtraq mailing list archives
RE: IIS SMTP component allows mail relaying via Null Session
From: "Toni Lassila" <toni.lassila () mc-europe com>
Date: Mon, 4 Mar 2002 08:13:03 +0200
-----Original Message----- From: Todd Sabin [mailto:tsabin () razor bindview com] Sent: Friday, March 01, 2002 17:31 To: bugtraq () securityfocus com Subject: IIS SMTP component allows mail relaying via Null Session Overview: IIS comes with a small SMTP component. The default settings allow anyone who can authenticate to it to relay email. Because the authentication system supports NTLM, it is possible for anyone to authenticate using null session credentials, and then relay email. Workarounds: Disable the SMTP service. Disable the ability of authenticated users to relay email. Firewall off the SMTP service from untrusted networks.
I suspect turning off NTLM authentication and allowing only Basic Authentication (with or without TLS), or alternatively disabling null session access (details are in many MS KB) from the server are two possible workarounds as well. Disabling null sessions is one of those security features one should do when securing a Windows-based server anyway. -- Toni Lassila t.lassila () mc-europe com Operations Engineer +358 9 5655 1882
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Current thread:
- IIS SMTP component allows mail relaying via Null Session Todd Sabin (Mar 01)
- <Possible follow-ups>
- RE: IIS SMTP component allows mail relaying via Null Session Toni Lassila (Mar 04)
- Re: IIS SMTP component allows mail relaying via Null Session Todd Sabin (Mar 05)