Full Disclosure mailing list archives
Re: A new TCP/IP blind data injection technique?
From: Valdis.Kletnieks () vt edu
Date: Thu, 11 Dec 2003 09:23:00 -0500
On Thu, 11 Dec 2003 10:56:01 +0200, Shachar Shemesh said:
fragment at the place you mention. Most TCP/IP connections employ PMTU discovery, and then split the stream at layer 4, rather then perform Layer 3 assembly.
I wish it were so. In fact, although many vendors ship with PMTU Discovery enabled, it very often gets turned off due to the extraordinary number of totally clueless sites that do one or more of: 1) Disable all ICMP, so the ICMP Frag Needed packets don't make it back, thus hosing the connection entirely (send too large packet, frag needed, ICMP dropped, timeout, retransmit, lather, rinse, repeat). 2) Number their point-to-points out of RFC1918 space, so the ICMP Frag Needed gets swallowed by some border router that's doing reasonable ingress/egress filtering. Most sites, if they have enough clue to realize the 576-byte default isn't all that hot, will simply nail the MSS to 1472 or so and pray for the best. Yes, that's not reliable either, but it works better than PTMUD does in the real world.
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- Re: A new TCP/IP blind data injection technique?, (continued)
- Re: A new TCP/IP blind data injection technique? Kris Kennaway (Dec 10)
- Re: A new TCP/IP blind data injection technique? Casper Dik (Dec 11)
- Re: A new TCP/IP blind data injection technique? Shachar Shemesh (Dec 11)
- Re: A new TCP/IP blind data injection technique? Michal Zalewski (Dec 11)
- Re: A new TCP/IP blind data injection technique? Shachar Shemesh (Dec 11)
- Re: A new TCP/IP blind data injection technique? Michal Zalewski (Dec 11)
- Re: A new TCP/IP blind data injection technique? Barney Wolff (Dec 12)
- Re: A new TCP/IP blind data injection technique? Michal Zalewski (Dec 12)
- Re: A new TCP/IP blind data injection technique? Stephen Frost (Dec 12)
- Re: A new TCP/IP blind data injection technique? Jeff Kell (Dec 12)
- Re: A new TCP/IP blind data injection technique? Michal Zalewski (Dec 11)
- Re: A new TCP/IP blind data injection technique? Kris Kennaway (Dec 10)
- Re: A new TCP/IP blind data injection technique? Mikael Abrahamsson (Dec 11)
- Re: A new TCP/IP blind data injection technique? Michal Zalewski (Dec 13)
- Re: A new TCP/IP blind data injection technique? Valdis . Kletnieks (Dec 13)
- Re: A new TCP/IP blind data injection technique? Michael Gale (Dec 13)
- Re: A new TCP/IP blind data injection technique? Michal Zalewski (Dec 14)
- Re: A new TCP/IP blind data injection technique? Michael Gale (Dec 15)
- Re: A new TCP/IP blind data injection technique? Michal Zalewski (Dec 15)
- Re: A new TCP/IP blind data injection technique? Michael Gale (Dec 15)