Re: Prevent banner grabbing

From: Jeff P. Van Dyke (jpv_at_vandyke.com)
Date: 12/11/03

  • Next message: Ashish Kumar: "SSH / PRIV SEP / LINUX issue"
    To: "Byron Sonne" <blsonne@rogers.com>, "Andrea Riela" <ml@nesys.it>
    Date: Wed, 10 Dec 2003 16:00:24 -0700
    
    

    > > I've a system with openBSD 3.3 and OpenSSH_3.7.1.
    > > How could I prevent a banner grabbing?
    >
    > You can't.
    >
    > As far as I know, the protocol spec *requires* the banner to be sent
    > so that connecting clients can determine what protocol versions to
    > use.

    The protocol requires the first part of the banner to be sent.

    For example:

      SSH-2.0-<version>

    I don't recall if OpenSSH lets you change this, but other
    implementations including ours allow you to configure the
    banner to be more generic. For example, changing it from:

      SSH-2.0-VShell_2_2_3_578 VShell

    to

      SSH-2.0-1.0

    Jeff P. Van Dyke
    jpv@vandyke.com
    www.vandyke.com


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