BugTraq
NetSky.q Virus. Looking for more detailed information on how the DOS will be performed. Mar 30 2004 06:18PM
Paul (paul edonkey2000 com) (1 replies)
Re: NetSky.q Virus. Looking for more detailed information on how the DOS will be performed. Mar 30 2004 10:03PM
Joe Stewart (jstewart lurhq com) (1 replies)
IPv4 fragmentation --> The Rose Attack Mar 31 2004 04:18AM
gandalf digital net (2 replies)
Re: IPv4 fragmentation --> The Rose Attack Apr 01 2004 12:07PM
Chris Brenton (cbrenton chrisbrenton org)
Re: IPv4 fragmentation --> The Rose Attack Mar 31 2004 08:07PM
stanislav shalunov (shalunov internet2 edu) (1 replies)
Re: IPv4 fragmentation --> The Rose Attack Mar 31 2004 11:42PM
Crist J. Clark (cristjc comcast net) (1 replies)
On Wed, Mar 31, 2004 at 03:07:31PM -0500, stanislav shalunov wrote:
> <gandalf (at) digital (dot) net [email concealed]> writes:
>
> > While this discussion pertains to IPv4, IPv6 also allows fragmentation and I
> > suspect IPv6 will also be affected by this attack.
>
> IPv6 does not have en-route fragmentation and, therefore, has no
> reassembly. IPv6 is not affected.

IPv6 does have end-station fragmentation, and therefore, it DOES have
reassebly, see Section 4.5 of RFC2460. I do not see why an IPv6
implementation would not also potentially be affected.

This is YANFA, Yet Another IP Fragmentation Attack. Teardrop, Ping O'
Death, NewTear, Boink, yada-yada. Some have exploited bugs in
reassembly code (over lapping frags, >65535-byte packets, etc.) and
others, like this, are flat out resource exhaustion DoSes.

The IP stack needs to be sane about how many datagrams it will try to
reassemble at once. This attack points out that when considering that,
you need to account for the fact a malicious attacker might eat
reassembly resources much faster than his bandwidth would seem to
indicate (two small packets can look like almost 65535). The other
approach is for the reassembly algorithm has to be careful about how
it allocates buffers for reassembly.
--
Crist J. Clark | cjclark (at) alum.mit (dot) edu [email concealed]
| cjclark (at) jhu (dot) edu [email concealed]
http://people.freebsd.org/~cjc/ | cjc (at) freebsd (dot) org [email concealed]

[ reply ]
Re: IPv4 fragmentation --> The Rose Attack Apr 01 2004 02:21AM
stanislav shalunov (shalunov internet2 edu)


 

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