Subject: Re: localhost security hole
To: William Allen Simpson <>
From: Andrew Brown <>
List: tech-security
Date: 06/28/2003 14:14:04
>Having proved beyond all shadow of a doubt that sending mail to 
>root@localhost leaves a security leak a mile wide, what should be done?

no, it doesn't.  you fail to understand what's going on.

>The zone administrator (or DNS spoofer) can redirect all root mail, by 
>adding a zone entry "localhost.dom.ain." that points to some other 
>place than  Is this considered a feature?

that doesn't matter.  that will only be looked for if "localhost" by
itself is not found.

>I proposed PR install/21999, to modify the /etc/hosts file to include 
>"localhost.dom.ain", right next to the "host.dom.ain host" line.
>So far, most commentators oppose this change.

sendmail knows to deliver to "localhost".  it looks up "localhost" and
finds  when it attempts delivery there, it also looks up so that it can put a canonicalized name in the
logs.  in your case, that maps to "".  you
need to fix that, but i don't believe it's a problem.

|-----< "CODE WARRIOR" >-----|             * "ah!  i see you have the internet (Andrew Brown)                that goes *ping*!"       * "information is power -- share the wealth."