DDoS Targeting Firewalls, Intrusion Prevention

Top 10 Security Stories Of 2010

Distributed denial of service (DDoS) attacks have broken the 100 Gbps barrier, increasing in bandwidth by 102% over the past year, and by 1000% since 2005.

That finding comes from an infrastructure security report, released on Tuesday by DDoS protection and network security vendor Arbor Networks. The company surveyed 111 self-classified Tier 1, Tier 2, and other IP network operators from around the world, and found the volume and severity of attacks continues to increase.

"Network operators are facing a global Internet insurgency driven by the ubiquity of botnets. This has led to rapidly escalating DDoS attack size, frequency, and sophistication," said Roland Dobbins, a solutions architect at Arbor Networks, in a statement. "Adding to the challenges facing operators is the increasing number of attack vectors, including applications and services, not to mention the proliferation of mobile devices."

Historically, DDoS attacks involved flooding Web servers with so many fake packets that they choked. But Arbor says that attackers are increasingly targeting specific network weaknesses, such as misconfigured domain name servers (DNS), which require relatively fewer resources to knock offline. Last year, according to the report, 77% of network operators detected DDoS attacks targeted at their application layer, including DNS and Web portals.

Surprisingly, placing a stateful firewall (which attempts to track the state of network connections when filtering packets) or intrusion prevention system (IPS) in front of a Web server can create another effective DDoS attack vector. "These devices can render networks more susceptible to attacks as the state tables on even the most scalable versions available can be overwhelmed with a moderate size DDoS attack," said Arbor. Indeed, half of the Internet data center operators surveyed said they'd experienced a firewall or IPS outage as the result of a DDoS attack.

As the sophistication and scale of DDoS attacks continues to increase, the report finds network operators struggling to keep up. In particular, they face insufficient security team funding, a shortage of skilled talent, poorly defined employee responsibilities, and incomplete security policies.

Interestingly, when network operators do experience a security breach, they're unlikely to report it to law enforcement. "This is due to both a lack of network operator resources and a lack of confidence in the ability of law enforcement to successfully investigate these incidents, especially in a multijurisdictional context," said Arbor.