Open Projects Net: Denial of Service Attacks
Posted 7 Nov 2000 at 08:41 UTC by lilo
Open Projects provides interactive facilities for coordination and
support to groups and projects involved with open source. We run
between 1,500 and 2,000 clients and are home to such projects as Debian
GNU/Linux and Enlightenment. We've had our
share of difficulties recently, but we're continuing on.
The past few weeks have been quite an experience. Last week one of our
on Open Projects started going up and down like a yoyo. I'd seen that
behavior in this normally very reliable server in recent weeks and not
thought much of it, since the company in question was in the process of
moving its facilities and reliability issues do sometimes creep in
moves. But we soon obtained a little bit more insight into the problem.
After watching the server perform a loop-de-loop, I received a /MSG
from a rather peremptory and anonymous skript kiddie informing me that
if I didn't
permanently remove the sponsor's server from the network, he would kill
line and take down Open Projects until he got his way. It seems he
the sponsor owes him money. I'm afraid I wasn't very polite in my
Feeling that one can hardly allow psychotic delinquents to dictate
policy, I explained to him that while he might very well be able to take
down our network, he was not going to set policy, and specifically I
not entertain the notion of removing our sponsor's machine.
The last week has been interesting. Apparently this petulant child has
something over 45Mbps to play with, and he's moderately competent with
attacks and so on. In various incidents throughout the week he packeted
ISP's and universities and small companies to death to demonstrate his,
prowess with borrowed equipment. Currently he has proclaimed that he'll
taking down our network once a day for an hour until his wishes are
All I can say is that he's going to be doing it for a long time if
the case; the heat death of the universe isn't due to arrive for some
Throughout this experience I have noticed it's very difficult to
much of a response from ISPs and backbone providers. An unofficial
at uu.net explained that we must notify his security people while an
was taking place for them to have any chance of thwarting it. They
thoughtfully provided him with an email address rather than a telephone
number to give to us, explaining that this is a matter of policy.
understand that packeting can affect services like email. Or perhaps
are simply extremely comfortable, their owners having cornered much of
backbone market after the last round of industry mergers. My employer's
was targeted, and so far the people at the ISP seem a little bewildered,
though they're game to fight the good fight. Some folks with very nice
bandwidth contributed a server today to see if we couldn't keep our
working through an attack, and the skript kiddie seems to have gone
their routers, leaving very little in the way of evidence behind him as
his point of origin.
As a first, one of our admins contacted the FBI at our request. I'm not
sure this will accomplish anything useful, but it's certainly worth a
It is worth noting that, as a philosophical anarchist, I'm usually not
inclined to bring in the muscle of a law enforcement agency to resolve
disputes, preferring to reason with the party or parties involved. But
cases where the problem user has learned his manners from repeated
of Robocop, well, there's not much one can do but consider the
business to be a declaration of war.
At any rate, it seems to me that this otherwise very mundane set of
points to a long-standing problem with the Internet: Denial-of-service
attackers have location indirection, but content services and users are
sight as targets for their efforts. I'm hoping Corridors will helpful in dealing with this
problem, though it's a fairly long-term project (and constantly in
additional expertise to finish the design and begin the
actual implementation). Meanwhile, we
go on, attempting to devise kludges to improve the
of ircd in the face of all-out attack.
Any assistance from the
in combatting problems which we have never experienced in quite this
magnitude would be greatly appreciated.
Thanks to the Magenet people and Diane Bruce and F. John Rowan of the
ircd project for their assistance. Thanks to the many users and admins
of OPN, whose patience and support have been impressive. And thanks
especially to VA Linux
their help and support; they've been real heroes and deserve a great
praise. And no, we're not going to delink their server, however many or
seconds we have to comply. ;)
There are, already available or coming onto the market, a variety of tools that can limit the impact of such denial of service attacks.
They are based on Diferentiated Services and QoS (Quality of Service). What makes these tools nice is that they allow you to limit, at
router, the amount of bandwidth that can be eaten by any single connection or group of connections, although that is not the only option
available. Assuming you have, or can get, policy enabled routers of some type (Cisco and Bay/Nortel are the 2 that spring to mind) you
can start limiting the impact of your friendly neighbourhood script kiddy fairly quickly.
There is, of course, a bad news side to this story. DiffServ and network traffic shaping in general are fairly new to the world,
honesty, the standards are somewhat of a moving target these days. There is very little agreement between the vendors and IETF on
even simple things like definitions, so a large dose of caveat emptor is required.
The other part of this you will need to look at is the management side of DiffServ. There are at least a couple of front-ends for
managing router policy and network policy, some better than others. Since my day to day job revolves around these things, I'll leave it
others less directly involved to discuss the specific vendor options here. My answer would be unashamedly biased in favour of a
vendor, and this is not the place for such things :)
I realize there isn't a lot of detail here, and I apologize for that. DiffServ and router/network policy is a very large and complex
Rather than occupy a large amount of space explaining options and uses, I think you and your employer would be better served by a
healthy dose of research. I would be more than happy to point you at my employers options in this area, outside this forum, if you're
interested and I could provide more detailed information if that is appropriate to your needs. Please note that this is potentially a very
expensive option, and there is not (to the best of my knowledge) an open source solution in this area. The benefit is that not only can
limit the potential damage from DoS', but it opens up a vast array of options in controlling how your available network resources are
Thanks for your comments, rasputin. One of the
problems is that Open Projects is a relatively-distributed network, and
that we depend on our sponsors for server account space. I believe
that, in the long term, such problems are best resolved by adding
client-server and client-client indirection which, in the current design
of the Internet, would have to be implemented in an additional protocol
In the meantime, we struggle along as best we can. Did I mention to
anybody that their cryptographic and steganographic experience would be
very useful to the Corridors project? :)
:) Anyone who is interested can send email to me at the feedback
address found on my
Go DoS!, posted 8 Nov 2000 at 09:28 UTC by k »
Being involved with IRC networks on and off for quite some time, it
surprises me that such a well understood problem like DoS can still
It is laziness in the network administrators, pure and simple.
This exact subject has been discussed to death on lists such as NANOG,
is well-known that QoS and related tools will not help a DoS type
network will still get the traffic, because the larger networks are ..
BUT, I don't think its up to the larger networks to filter traffic. The
"internet design" and its very heavy asymmetry in routing paths makes
in the core very difficult. The problem lies in filtering customer
shouldn't be able to send spoofed packets unless they have a good reason
half-duplex satellite feeds). And even then, you're talking about 1% of
online population who needs this.
*sigh* I think you're stuck Lilo. Track the script kiddie down and
squash him. He'll
either get caught, or he'll stop.
On a humerous note, I find the two versions of "DOS" both equally
*sigh* I think you're stuck Lilo. Track the script kiddie down and
squash him. He'll either get caught, or he'll stop.
That pretty much nails it. Spoofed IP packets need to be squashed at
origin, which essentially requires the cooperation of all of the
providers, since skript kiddies will tend to find providers which don't
comply. The answer has ultimately got to be location indirection for
content nodes (client and server), <tireless-recruiting>which is what
the Corridors project is all
Another comment I wanted to make here: To clarify, it seems very
unlikely that the skript kiddie has a real grudge against VA.
Regardless of the rationalizations he just seems to enjoy watching
people ping out....
Pretty much no other instant messaging system seems to have these kinds
of problems with mass DOS attacks. I think the problem is more social
than technical - IRC attracts the wrong kind of crowd.
Pretty much no other instant
messaging system seems to have these kinds of problems with mass DOS
attacks. I think
the problem is more social than technical - IRC attracts the
wrong kind of crowd.
I would argue that it's a
combination of problems. IRC networks handle the largest user base of
the interactive messaging systems available. Handling a large user base
is potentially a very powerful thing....if you can connect people well
to each other, and encourage random conversation. But IRC was never
meant to scale to the size it has, so it lacks good indexing of
interaction areas and some other things.
But it's just a fact that if you connect a lot of people together, some
of them are going to want the feeling of power you get from a DoS
attack. That ability to deny service needs a technical solution, and
location indirection seems to be essential.
Corridors mania, posted 9 Nov 2000 at 21:33 UTC by ovek »
It's obvious that with the widespread popularity of IRC, surely someone
else (MANY else) would have thought of and refined new IRC-server
designs long ago, right? So in what way would your Corridors be related
to the design work of these visionaries, trying to come up with irc3, the
next generation of distributed IRC service? I think you're much more
likely to get developers if you can coordinate with the old irc3
designers and be able to call your new project the official irc3
I think you're much more
likely to get developers if you can coordinate with the old
irc3 designers and be able to call your new project the official
I'm not sure that would be the right approach. The transport
architecture of Corridors
is intended to
have a completely different emphasis than the transport structure of
irc3; location indirection is key and it's considerably more
decentralized. And the interactive service is just one service laid on
top of the
transport layer, and it's really not a whole lot like irc, in emphasis
There is nothing wrong with having a number of projects to do
overlapping things. With a relatively large number of projects, one or
more is more likely to take off and serve a need. In my opinion, we do
no one a favor
to try to merge approaches and reduce the diversity of potential
Maybe not, but since irc3 is still so much well-designed vaporware
itself, I thought your project would at least benefit a lot from looking
at their design proposals, and the irc3 team would probably give you
their blessing immediately because they don't have their own
implementation anyway. Something to consider, I thought?
DoS Approaches, posted 20 Nov 2000 at 04:48 UTC by Ankh »
On SorceryNet we have a number of approaches to denial of service attacks,
although massive packet flooding is one that's just not easily solved. We try and promote a culture in which people are
erspected as individuals, and yet remain intolerant of nuking, port scans, "hacker talk" and so forth. On the technical side, we
don't allow connections from open wingate servers, which helps a little. But the IRC infrastructure is fragile, and easily upset.
Like you with corridors, I've been working on irc++,
intended to be a more robust and scalable service (the paper there is a very incomplete draft of a conference paper).
One problem we had at SorceryNet was a skript kiddie who worked at a major ISP; he happily packet flooded us, and
complaining to the ISP was not likely to help. Luckily for us, he went away again; my next recourse was going to be to contact
the board of directors for the ISP involved.
The latest problem seems to be massively distributed attacks using sub7 bots. These bots can usually be disinfected
remotely, but it's a real pain to have a few hundred bots all join and start flooding. Again I think the real problem is cultural, but
there is also the problem of (effectively) anonymous internet use destroying accountability. I do0n't have an answer to that.
Again I think the real problem is cultural, but there is also the
problem of (effectively)
anonymous internet use destroying accountability. I do0n't have an
answer to that.
The right approach to accountability is to harness trust models. I'm
not averse to anonymity. The problem in the typical distributed
denial-of-service attack is that the attacker has location anonymity,
but the service he's attacking does not. The latter needs to be
changed, to give the attacked party the tools to deal effectively with