High bandwidth DDoS attacks are now common, researcher says

IDG News Service - Distributed denial-of-service (DDoS) attacks with an average bandwidth of over 20Gbps have become commonplace this year, according to researchers from from DDoS mitigation vendor Prolexic.

Last year such high-bandwidth attacks were isolated incidents, but attacks that exceed 20Gbps in bandwidth occur frequently now, Prolexic's president Stuart Scholly said Tuesday.

This is significant because very few companies or organizations have the necessary network infrastructure to deal with such attacks. There might be some companies with popular websites such as Google or Facebook that are able to handle such high-bandwidth floods, but most companies are not, Scholly said.

Prolexic plans to upgrade the capacity of its own cloud-based DDoS mitigation infrastructure in order to keep pace with the increasing volume of high-bandwidth attacks, he said.

The company released its global DDoS attack report for the third quarter of 2012 on Wednesday. According to report, there's been an 88 percent increase in the overall number of attacks compared to the same period of last year. However, compared to the second quarter of 2012, the number of attacks actually declined by 14 percent.

The average attack bandwidth during the third quarter of 2012 was 4.9Gbps, which represents a 230 percent increase compared to a year earlier, and an 11 percent increase compared to the previous quarter.

The average attack duration during the third quarter of this year was 19 hours, slightly longer than in the second quarter.

The majority of attacks -- over 81 percent -- targeted the infrastructure layer, while 18.6% of attacks targeted the application layer, protocols used by specific applications.

The top three countries from where DDoS attacks originated were China with 35 percent of attacks, the U.S. with 28 percent and India with 8 percent.

In the case of high-bandwidth DDoS attacks, a change in attack tactics has been observed, Scholly said. Instead of using botnets of compromised personal computers, such attacks are launched from botnets of compromised servers. The attackers gain access to such servers by exploiting vulnerabilities in outdated Web applications and install PHP-based DDoS toolkits.

One toolkit that has recently been used to launch high-bandwidth attacks against multiple financial institutions in the U.S., as well as companies from other industry sectors, is known as "itsoknoproblembro."

It's not clear if this toolkit is sold on the underground market, but evidence suggests that it is being constantly improved and is used by multiple groups of attackers, Scholly said. Attackers don't need administrative (root) access to a compromised server in order to install the toolkit and launch attacks with it, Scholly said.

"Itsoknoproblembro" allows attackers to react faster to any defenses they might encounter and modify their attack strategy. That's because they can send commands to servers infected with the toolkit almost instantly, while in the case of traditional botnets they have to wait for the bot clients to periodically fetch new instructions from a command and control server.

Clean-up efforts for infections with "itsoknoproblembro" are difficult because of outdated applications and inexperienced server administrators, Prolexic said in its report. The company plans to release a public advisory that will contain fingerprinted signatures for DDoS attack variants supported by the "itsoknoproblembro" toolkit that will help others detect and mitigate such attacks.