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Re: (ASCEND) Ascend DoS attack



Might have been a problem with OSPF (lately I've noticed it to be getting
flaky again) on the MAXen, but I'm not sure.  I don't have the luxury of
being able to test this, since I have very little test equipment.  

BTW, what version of the code did you test this on?

Joe Shaw - jshaw@insync.net
NetAdmin - Insync Internet Services
"Learn more, and you will never starve." - Paraphrase of Lee

On Sat, 28 Jun 1997, Jason Nealis wrote:

> 
> 
> Ok, This did not work in my enviroment, We Run rip and straight
> IP here, And I repeatedly tried to get the MAX to accept my IP address
> and it kept assigning my IP's outta the pool.
> 
> This was with the K56 Card support load also, so I believe that would
> make it tik.m40, 4004 boxes, 
> 
> Jason Nealis
> Erols Internet
> 
> 
> On Thu, 26 Jun 1997, Joe Shaw wrote:
> 
> > Problem:
> > Recently, we noticed a problem in Ascends microcode for the Ascend MAX
> > 4000 that allowed any user to request any IP address they wanted.  This
> > problem surfaced in the 4.x versions of code, works on 5.0Ap8, and
> > probably works on most of the versions of Ascend software.
> > It was fixed originally some time ago (or at least thats what I was led to
> > believe by Ascend), but the problem resurfaced recently.  It will work,
> > even if you have such things as Assign Adrs and Pool only set to yes.
> > 
> > The problem can be duplicated by just making your settings in windows
> > Dialup Networking say Specify IP Address, and then setting it to the ip
> > address of a machine on the network you're connecting to.  Once connected,
> > I telneted from another machine to our router, and sure enough, when I did
> > a show ip route xxx.xxx.xxx.xxx, it showed that it was being broadcast via
> > OSPF from one of our MAXen, instead of being connected directly to FDDI0.
> > I assumed I couldn't get out to the network, but in attempting to telnet
> > out from the dialin box, I got to our core cisco and the other machines on
> > our network.
> > 
> > Possibilities:
> > The ability to take any IP address means that a dialin user can take the
> > IP address of a DNS server, a router, anything with an IP address.  In
> > some instances (where proxy mode is enabled on the MAX) you will be able
> > to still route to some machines, while not being able to get to others
> > (this depends on the network setup).  Also, it's possible to take the IP
> > address of one machine by simply dialing up, and while doing so, you could
> > possibly rcp over a password file or any other file you wanted to as long
> > as the ip address of the machine is trusted.  This makes any service that
> > works strictly off of authenticatino of IP address extremely vulnerable.
> > You could take over DNS services, grab passwords for people checking pop
> > mail, and anything else you can think of.
> > 
> > Solution:
> > After some poking around, I upgraded all the MAXen to the latest
> > version (5.0Ap13), which seems to have fixed the problem.  I know most
> > Ascend users are leary of doing this, since features are fixed, then
> > broken in later versions of code.  But, 5.0Ap13 has been working since the
> > begining of this week and has proven to be stable doing multi-chasis
> > stacking and OSPF.
> > 
> > Sidenotes:
> > I don't know if this will work on the MAX TNT, but I'm fairly sure it will
> > work on the MAX4002, MAX4004, MAX4048, and MAX4072.  If you have one of
> > these units, I'd test and make sure, and if you're vulnerable, get the
> > latest version of code off ftp.ascend.com.
> > 
> > Joe Shaw - jshaw@insync.net
> > NetAdmin - Insync Internet Services
> > Learn more, and you will never starve.
> > 
> > ++ Ascend Users Mailing List ++
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> > To get FAQ'd:	<http://www.shore.net/~dreaming/ascend-faq>
> > or		<ftp://ftp.shore.net/members/dreaming/ascend-faq.txt>
> > 
> 
> 

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