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North American Network Operators Group Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical Re: If you have nothing to hide
In message <[email protected]>, [email protected] et writes: > >> >> >> "You know, there's quite a difference between source routing and >> IP spoofing .." >> >> >> >> As true as this statement is, the two walk hand in hand (especially during >> certain attacks). >> >> If I send an attack from a spoofed address to a victim, I can turn blue in >> the face waiting for a response that will never come. >> If I spoof an address and use loose source routing I can force the response >> to return right through my network. > >I was not aware that responses to source-routed packets were themselves >source-routed. I also don't believe it is the case, but am open to being >contradicted. If the responses aren't source-routed, then the packets would >only return through your network if your network was the path back to the >spoofed source. See section 3.2.1.8c of RFC 1122: If host receives a datagram containing a completed source route (i.e., the pointer points beyond the last field), the datagram has reached its final destination; the option as received (the recorded route) MUST be passed up to the transport layer (or to ICMP message processing). This recorded route will be reversed and used to form a return source route for reply datagrams (see discussion of IP Options in Section 4). When a return source route is built, it MUST be correctly formed even if the recorded route included the source host (see case (B) in the discussion below). --Steve Bellovin, http://www.research.att.com/~smb (me) http://www.wilyhacker.com ("Firewalls" book)
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