Full Disclosure mailing list archives

Re: A new TCP/IP blind data injection technique?


From: Valdis.Kletnieks () vt edu
Date: Sat, 13 Dec 2003 15:04:10 -0500

On Sat, 13 Dec 2003 03:35:25 MST, Michael Gale <michael () bluesuperman com>  said:

For example the BorderWare Firewall will not accept fragmented packets,
they are working on a firewall function that when fragmented packets
arrive. It will save the first piece plus all frags until the final one
is received. But the packet back together and do a sanity check of some
sort. Then pass or drop the packet.

So the problem is that the host may re-assemble a fragmented packet with injected
data in it.

And we protect against it by.... you got it.. having the firewall re-assemble the
fragmented packet with injected data and then handing the re-assembled full
packet (with injected data) to the host.

Whoops.

Attachment: _bin
Description:


Current thread: