http://www.internetnews.com/dev-news/article.php/10792_1573551

By Thor Olavsrud
January 24, 2003

For at least a month, distributed denial of service, or DDOS, attacks
have been crippling DALnet, one of the world's largest Internet Relay
Chat networks, bringing it to its knees and raising the possibility
that many hosting providers may refuse to host IRC servers at all.

"DALnet is presently suffering extensive and prolonged Distributed
Denial of Service attacks against our IRC servers, Web server, mail
servers and DNS systems," DALnet said on its Web site. "These attacks
are causing great inconvenience and financial loss to many of the
organizations that host our services, as such some of them have
suspended or discontinued their support of DALnet."

IRC, developed by Jarkko Oikarinen of Finland in 1988, allows people
connected anywhere on the Internet to join in live discussions. Each
discussion is on a "channel," and many people can join at once. DALnet
was one of the earliest IRC networks, formed by users of EFnet (Eris
Free Network) in June 1994 because of the netsplits (caused when the
connection of one or more servers in a network is broken) and lag that
were plaguing that network. DALnet pioneered Services, which allowed
users to control their presence online without being harassed or
having channels stolen from under them.

But these days DALnet -- which is manned by volunteers and run with
equipment and bandwidth donated as a service to the Internet community
-- is hanging on by a thread as sustained DDoS attacks flood its
servers and even threaten the networks that host its servers. The
attacks have forced DALnet's administrators to take down most of its
client servers and leave them down rather than risk taking down its
hosts.

"Yes, as you all know, DALnet has been attacked again by criminals
who, for reasons known only to themselves, choose to spoil the
enjoyment of so many," Emma/Curve, chief editor of the DALnetizen
ezine and one of DALnet's administrators, wrote in the January issue
of the ezine. "These latest attacks are worse than any of the server
administrators have seen before, attacks large enough to cripple the
networks which host our servers, let alone the servers themselves."

The attacks come in the form of 'botnets,' whole networks of malicious
bots (define), created by Trojans (define), which flood DALnet's
network with packets. According to Curve, those packets are coming in
at a rate of Gbps (define).

"It's no secret that DALnet has suffered massive attacks recently, far
greater than anything we've seen before," she said. "We've been
ravaged by DDOS attacks in the Gbps range, attacks which are not just
crippling our IRC servers, but causing disruption to the providers who
host those servers."

She continued, "Why do I say that more than DALnet is at stake? Well,
because the more these people amass herds of infected computers
(botnets) to attack IRC servers with, the more service providers will
quickly come to the conclusion that hosting an IRC server is a
liability. Already many providers simply won't countenance hosting an
IRC server and if this random vandalism continues, the harder it will
be for non-profit IRC to continue in any reasonable form at all. That
could jeopardize the future for all IRC networks, not simply DALnet."

The Trojan spreads through e-mail, or even when a user visits a Web
site with a bit of hidden code, and the users won't know unless their
anti-virus software is up to snuff. Once the Trojan makes its way onto
a machine, the next time that computer connects to the Internet the
Trojan will start up an IRC client and connect to a server -- often an
IRC server set up on a shell account and paid for with a stolen credit
card. The Trojan then creates a bot which is programmed to join a
certain channel once it has connected.

A successful Trojan which has propagated widely can fill a channel
with bots. Curve said she and other members of DALnet's Exploits Team
have seen channels with as many as 4,000 to 5,000 bots -- each a home
computer infected with a Trojan. A collection of such bots in a
channel is a botnet.

Once the person who wrote the Trojan comes online, the botnet is
waiting for him, and he can use it for a number of things, the worst
being a DDOS -- using hundreds or thousands of bots to send data to a
server until its connection becomes saturated and it crashes. Not only
does such an attack inconvenience chatters using IRC services, it can
also affect the service providers who host IRC servers, preventing
their customers -- even ones who don't use IRC -- from going online.

"It could be surmised that people who launch DDOS attacks know their
intended target and can find enough bandwidth to bring the target
down," Aaron Schultz, a provider of DALnet hosting, wrote in the
January issue of DALnetizen. "The problem that most don't seem to
think about are the related networks which also get hit. The small ISP
which has an infected customer who suddenly starts using all available
bandwidth, the nationwide latency created on some networks due to the
amount of packets or the small businesses that have servers on a
network near the intended target."

"Another example of innocent targets being hit are when ISPs
experience nationwide latency and regional outages due to these
attacks," he wrote. "Are the attacks that I receive that have caused
such major outages attacks on me, or the entire U.S.? And should all
of the ISP's Southern California customers be taken offline just
because of someone's disagreement with DALnet? No."

DALnet administrators continue to hold out hope that the situation can
be resolved. DALnet said it is working with a number of law
enforcement agencies to track down those responsible, has lodged
complaints with the ISPs it has been able to trace, and has the help
of experts in dealing with DDOS attacks.

So when will the attacks stop? "We don't know," DALnet said. "They
will stop when either the attackers decide to stop attacking, the
attackers get arrested or shut down by their ISPs, or when DALnet runs
out of goodwill from its sponsors and is forced to close."

Anyone with information about the attacks is asked to submit it to
DALnet's contact form.

http://kline.dal.net/exploits/info.htm

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