Re: Securing webmail - changing a port necessary to ensure security?

From: Ansgar -59cobalt- Wiechers (bugtraq_at_planetcobalt.net)
Date: 02/12/04

  • Next message: Thiago Lima: "RE: Securing webmail - changing a port necessary to ensure security?"
    Date: Thu, 12 Feb 2004 13:54:58 +0100
    To: security-basics@securityfocus.com
    
    

    On 2004-02-11 Jennifer Fountain wrote:
    > I am going back and forth on this one with a consultant on this one and
    > need an expert opinion. So, I turn to you :)

    Hope you don't mind me answering instead ;)

    > When configuring webemail (such as owa) that is using https, is it
    > better to change the default port (443) to an uncommon port (20000)for
    > security reasons? Does it secure it further by doing this?

    No. Security by obscurity won't work since an attacker could simply run
    a portscan against your webmail host to determine which ports are open.

    > Wouldn't it cause more issues than anything if you try to access that
    > site from inside an org that only allows port 80/443 and 21 out?

    If you allow 21 out, you will also have to allow 1024+ out, since
    passive FTP opens the data connection on a high port IIRC. So no, using
    port 20000 won't cause problems in that scenario, but it also won't
    improve your security.

    Regards
    Ansgar Wiechers

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