Firewall Wizards mailing list archives
RE: RPCs over HTTPS through the firewall
From: "Ben Nagy" <ben () iagu net>
Date: Fri, 25 Apr 2003 10:01:17 +0200
-----Original Message----- From: Mark Tinberg [mailto:mtinberg () securepipe com] [... On Tue, 22 Apr 2003, Ben Nagy wrote: [snip]Finally, "conventional" port 443 traffic basically containsunsecured,unsecureable rubbish, passing through the firewallencrypted, so thatit's all one Big River of Risk as far as an admin isconcerned. Doesit matter much if we add RPC to the sludge? Nnnnnnnope.I would not agree with that.
OK. But even when taken out of context I think I can still back it up...
HTTP traffic over 443 or 80 has a similar risk profile, although encrypting traffic over 443 prevents several types of shenanigans that can be had on the intervening network links.
I think the point is that port 443 doesn't just contain HTTP traffic anymore, and from an admin point of view it's impossible to tell. The risk profile of port 443 isn't really congruent with that of HTTP, and it is one of the firewall admin's major bugbears.
RPC on the other hand generally exposes a much richer interface, directly into the core of the OS that generally was never designed with security as even a tertiary concern.
Which is why it's directly exposed on most OSes through the endpoint / port mapper, right? C'moooonnnnn. And what's this "directly into the core of the OS" stuff? RPC lets distributed apps call functions remotely. Yes, it's low level, but that's not saying the same thing. If you allow, for example, remote registry access (which uses RPC) _then_ you're exposing the core of the OS, but RPC doesn't really expose anything by itself.
There are way more things that can go wrong and you have far less access control opportunities than with a web service.
(URL will wrap) http://www.googlefight.com/cgi-bin/compare.pl?q1=RPC+exploit&q2=Web+exploit& B1=Make+a+fight%21&compare=1&langue=us According to Googlefight (mmost acurate of sources ;) RPC exploit ( 45 800 results) versus Web exploit (1 140 000 results) Flippant, I know, but - sadly - it does reflect reality. It's ironic, really, that RPC has been one of the big unix "hack me" services whereas it is not one of the worst MS offenders. The Web service, however, has historically been the exact opposite. Before anyone gets all "platform agnostic" on me, the original question regarded Outlook traffic to an Exchange server, so excuse me for being windows centric here.
I would say that allowing RPC from random hosts on the Internet without at least authenticating the source before allowing the traffic through is a no-go.
That's very true. It's also pretty much unrelated to the discussion you snipped my quote from. Hardly sporting, old chap.
- -- Mark Tinberg <MTinberg () securepipe com> Network Security Engineer, SecurePipe Inc.
Cheers, ben _______________________________________________ firewall-wizards mailing list firewall-wizards () honor icsalabs com http://honor.icsalabs.com/mailman/listinfo/firewall-wizards
Current thread:
- RPCs over HTTPS through the firewall david singleton (Apr 21)
- Re: RPCs over HTTPS through the firewall Volker Tanger (Apr 22)
- RE: RPCs over HTTPS through the firewall Ben Nagy (Apr 22)
- RE: RPCs over HTTPS through the firewall Mark Tinberg (Apr 25)
- RE: RPCs over HTTPS through the firewall Ben Nagy (Apr 25)
- RE: RPCs over HTTPS through the firewall Gwendolynn ferch Elydyr (Apr 25)
- RE: RPCs over HTTPS through the firewall Mark Tinberg (Apr 25)