Nmap Announce mailing list archives
Re: firewalk meets nmap - TTL
From: Mikael Olsson <mikael.olsson () enternet se>
Date: Tue, 07 Nov 2000 20:54:21 +0100
Hmmm.. Already replied to this on fw-wiz, but I suppose people here could benefit from it aswell. Lance Spitzner wrote:
I sent this off to the nmap-list, was wondering what all the firewall weenies on board here thought. :0
Hah. Try that through our contrapments and all you'll get is a "DROP: TTL too low" entry in the logs >:] On the other hand, it may very well be very effective against plenty of firewalls out there, based on what I've seen. People tend to do filtering FIRST and then pass it to "route_ip()" or whatever, which does the actual TTL decrement and check. About a year ago, I talked to a couple of pen-testers about firewalk being able to detect hosts directly behind firewalls this way. One interesting side effect is that the firewall will have carried out address translation before passing it to the routing section, so the ICMP unreachable data passed back might contain private IPs. If memory serves me, I think they said there was some talk about this sort of firewalking on defcon'99 (but don't take my word for it). -- Mikael Olsson, EnterNet Sweden AB, Box 393, SE-891 28 ÖRNSKÖLDSVIK Phone: +46 (0)660 29 92 00 Direct: +46 (0)660 29 92 05 Mobile: +46 (0)70 66 77 636 Fax: +46 (0)660 122 50 WWW: http://www.enternet.se/ E-mail: mikael.olsson () enternet se On bosses and technology: "There are bosses who don't know, and there are bosses who don't know that they don't know" /Anonymous techie -------------------------------------------------- For help using this (nmap-hackers) mailing list, send a blank email to nmap-hackers-help () insecure org . List run by ezmlm-idx (www.ezmlm.org).
Current thread:
- firewalk meets nmap - TTL Lance Spitzner (Nov 03)
- RE: firewalk meets nmap - TTL Ofir Arkin (Nov 03)
- RE: firewalk meets nmap - TTL (tested) Lance Spitzner (Nov 04)
- RE: firewalk meets nmap - TTL (tested) Ofir Arkin (Nov 04)
- RE: firewalk meets nmap - TTL (tested) Lance Spitzner (Nov 04)
- Re: firewalk meets nmap - TTL Fyodor (Nov 05)
- Re: firewalk meets nmap - TTL Mikael Olsson (Nov 08)
- RE: firewalk meets nmap - TTL Ofir Arkin (Nov 03)