ISPs take on DDoS attacks


The largest ISPs are promising new tools by next year that will help predict and better defend against worms and viruses that act like distributed DoS attacks and true distributed DoS strikes.

Although the number and intensity of distributed denial-of-service attacks are on the rise, users are hard-pressed to find tangible new services to help thwart or defend against such assaults.

However, the largest ISPs are doing more behind the scenes and are promising new tools by next year that will help predict and better defend against worms and viruses that act like distributed DoS attacks and true distributed DoS strikes.

"There have been more attacks in the last six months than there have been in the last 10 years," said Hossein Eslambolchi, president of AT&T Labs, at a recent press conference.

Carnegie Mellon University's CERT Coordination Center for reporting Internet security problems backs up such claims. Through the end of September, there were 114,855 security breaches reported by users and ISPs, which is 32,761 more than all of 2002. These reports include all types of security policy violations from distributed DoS to hacker attacks.

Although there are more security violations, the types of distributed DoS attacks have not changed much in 12 to 18 months, says Paul Morville, director of product management at Arbor Networks, which offers PeakFlow network behavior anomaly detection products to service providers. What has changed is the size and scope of these attacks.

"Attacks used to be largely assigned to an individual host. These days, the attacks are very large coming from multiple points on the Internet and are targeted at a network," he says. Arbor is seeing zombie armies, which are compromised host machines, with as many as 50,000 hosts attacking one network, Morville says.

While VPNs and managed firewall services are available from many ISPs, the primary goal of these offerings is to secure traffic that travels over the Internet. The largest business ISPs don't commonly offer intrusion-detection services that include anomaly detection aimed at mitigating the effects of distributed DoS attacks.

But that likely will change in the next 12 months.

MCI, like AT&T and Sprint, is testing tools that are designed to detect distributed DoS attacks, and worms and viruses that act like distributed DoS by trying to eat up a target's bandwidth.

"Around mid-next year we'll deploy a solution that will enhance our detection ability so we can be more proactive," says Bob Blakely, security services product manager at MCI. The tools that MCI is looking at deploying include anomaly and intrusion-detection elements. MCI says it's testing a number of vendor products, including Arbor gear.

While MCI says it's been doing in-house traffic analysis, it has not deployed network-wide anomaly detection gear because the tools haven't been mature enough and there have been network scalability issues, says Christopher Morrow, manager of network router security at MCI.

In the meantime the service provider recently has put a couple of projects in place to better deal with the slew of attacks.

Morrow says that in the past it was difficult to find the correct person to notify at another ISP when an attack was originating from its network. Now many of the large ISPs are part of an e-mail and voice-over-IP mailing list of sorts. Network administrators communicate regularly over this informal system in an effort to stop an attack quickly.

MCI also says it's sharing best-practice guidelines with peers and customers. These guidelines deal with traffic surges stemming from a distributed DoS attack or from a worm or a virus that is sending a flood of traffic. MCI assists a customer to block, or blackhole, this traffic, or customers do it themselves based on the ISP's guidelines.

"In most attacks we can blackhole traffic within two to three minutes," Morrow says. While the ability to react quickly is helpful to customers, the ISPs and users agree it's essential to be proactive instead of reactive when dealing with distributed DoS.

One analyst agrees. "A number of clients have expressed dissatisfaction with their ISP's responsiveness regarding security," says Trent Henry, an analyst at Burton Group. "After the IT bubble burst, it seemed staff reductions across the board might have left some of the ISPs a bit strapped."

It's tough to say if the ISPs have done enough up until this point to protect against these types of attacks, Henry says.

"It's easy for a security analyst to cry wolf" and say the service providers should have known attacks would increase, he says. But it's not just about the security on the ISP's networks, but the lack of security patching from Microsoft and the number of Internet desktops with always-on connections. Microsoft platforms have been used in almost every zombie attack, Henry says.

Network behavior anomaly detection technology that's now available is an ISP's best bet at keeping a distributed DoS attack as close to the source of the attack as possible, which is key in mitigating the damage of these types of attacks across the Internet, Henry says. Now it's just a matter of getting this technology deployed.

AT&T says that it has built in some proactive, network-based security into its backbone, and it's looking at anomaly detection gear from Arbor. AT&T is looking at combining off-the-shelf tools with anti-distributed DoS technology that AT&T Labs has developed over the years.

"Arbor has a component that we rely on in terms of analysis, in addition to router logs," says Sanjay Macaw, director of IP security services at AT&T. Macaw, like his competitors, says there is no one technology or tool that will stop these attacks, but a combination of tools when used together should let ISPs reduce network downtime and damage from distributed DOS strikes.Calls to CERT

In the past 12 to 18 months, Macaw says AT&T has put a lot of attention on developing the edge of its network through traffic analysis and other security measures. The carrier is spending more in terms of the number of employees it has focusing on distributed DoS and other security threats, and the technology it uses to defend its networks.

Sprint too is focused on deploying new tools in its network to better arm itself. Sprint is specifically focusing on distributed DoS mitigation and intrusion-detection products that it plans to deploy in its backbone within the next year, says John Pardun, senior product manager of network-based IP VPN and security services at the carrier.

Today Sprint says it has a "strong network-based platform," that uses stateful inspection in its edge routers to examine traffic, Pardun says.

Sprint plans to offer customers an "additional level of monitoring and mitigation" to customers as an add-on service that it will charge for, Pardun says. Both MCI and AT&T also say they will charge customers for their planned distributed DoS services.

Although these additional services are not yet available, some customers say their ISPs are protecting their Internet connections to a degree. Flowserve works with AT&T, KPN, MCI, Sprint and Yipes to connect its five Internet gateways around the world.

"Each [ISP] has some preventive measures in place," says Pieter Scholhijs, director of worldwide IT infrastructure for Flowserve. But "I'm not sure if they've been put to the test for our particular connections," he says.

Scholhijs says that although the number of distributed DoS attacks has increased, it would be fair to say that his company has not seen an increase in bandwidth problems. This could be an indication of how well Flowserve's ISPs are protecting the company's network connectivity, he says.

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