Thanks for all the replies.
I think I didn't express myself quite clear, although most of the answers are useful :-) and/or atleast confirm what I was already guessing. The point is I'll have a linux firwall, connected to that the internet, a DMZ and a LAN. This linux firewall will have no open ports on any side. It will however forward some ports to the DMZ ofcourse :-) The DMZ will deny all traffic from the LAN <--> DMZ. I was figuring I still should be able to reach it, just not by it's internal address but by it's internet address, cuz if I'm right the firewall will do this: Client (outgoing) -> Lan (eth0 incoming) -> ppp+ (loopback outgoing) -> ppp+ (loopback incoming) -> lan (eth1 outgoing) -> dmz Assuming I use the internet address and not the dmz local IP. So that should work. Since it will use internal loopback this should be as fast as LAN -> DMZ. Now the point is, the DMZ can be compromised, how much risk is there, from either the internet or the DMZ, that the firewall can be compromised with NO open ports. I somewhere heared once it was possible. But it think people that are that advanced are hard to find, or perhaps it was just someone bragging :/ Anyways, thanks for all the help so far. Kind regards, Ferry van Steen InfoPart Automatisering B.V. Beeksestraat 24 4841 GC Prinsenbeek Phone: +31 (0)76 - 5 44 04 11 Fax: +31 (0)76 - 5 41 83 51 Mobile: +31 (0)6 - 28 46 47 45 E-Mail (business): [EMAIL PROTECTED] E-Mail (private): [EMAIL PROTECTED] MSN Messenger: [EMAIL PROTECTED] ICQ (UIN (seldom used)): 191458 -----Original Message----- From: Karma [mailto:[EMAIL PROTECTED]] Sent: donderdag 11 juli 2002 2:28 To: Ferry van Steen Subject: Re: Cracking a server without services Sure. Unfortunately you might find that statistically, almost 90% hacks comes from internal network. One example of such attacks could come from say the "Debug" security flaw in Win NT that allowed the software GetAdmin and GetAdmin II to gain Administrator priviliges. The other example, such as Debploit which can be used to give SYSTEM account privilege to virtually any running process. Lets not even begin to talk about "emails" and "trojans", that is a large can of worms. About your DMZ question on the other post. I have no idea what this is "Draytek Vigor2200Wplus". But you have to remember, the DMZ is regarded (IMO anyways) as the external network. Your firewall should be set only to allow certain services (such as WWW or SSH etc) to be seen from external networks (only if required). The servers on your DMZ is then, only as secure as how secure your servers have been setup. And if you have any form of IDS etc that helps too. Otherwise the rule is to not allow access from your DMZ to your internal network, such as login names, passwords, domain information, ALL SHOULD BE DIFFERENT. your internal network and DMZ, there are numerous ways to do this, but whatever it is, regard the DMZ servers as external and dangerous and your internal network should be quite happy. HTH ----- Original Message ----- From: "Ferry van Steen" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Thursday, July 11, 2002 2:09 AM Subject: Cracking a server without services > Hey there, > > I was just wondering. I know the rule is everything can be cracked. But can > anyone point me to info on how to crack something with no ports open or/and > perhaps tell me how that's called (so I can search...). To me it seems > impossible but I have a feeling that's a false sense of security and I'd > like to get a better understanding of this so I can take appropiate actions > on my servers. Also I think this knowledge will come in handy in the future > since I gotta write a firewall on linux for a DMZ and LAN set up in like a > week or so and I don't want to tell my boss that the webserver is the only > thing that can be cracked because that's the only service we run if that > ain't so, although the chance someone with that knowledge/expertise will > hunt us will probably be nihil. > > Kind regards, > > Ferry van Steen > InfoPart Automatisering B.V. > Beeksestraat 24 > 4841 GC Prinsenbeek > Phone: +31 (0)76 - 5 44 04 11 > Fax: +31 (0)76 - 5 41 83 51 > Mobile: +31 (0)6 - 28 46 47 45 > E-Mail (business): [EMAIL PROTECTED] > E-Mail (private): [EMAIL PROTECTED] > MSN Messenger: [EMAIL PROTECTED] > ICQ (UIN (seldom used)): 191458 > > > >
