Security Experts:

Multi-vector DDoS Attacks Grow in Sophistication

A new report from Arbor Networks shows that while the size of distributed denial-of-service attacks have started to plateau, application-layer and multi-vector attacks continue to evolve.

In a survey of 130 network operators, Arbor found that 46 percent reported multi-vector attacks that use combinations of volumetric, state-exhaustion and application-layer attack vectors to hit organizations at the same time. These attacks are challenging, the firm argues, because they require layered solutions across the data center and the cloud to be mitigated successfully. This is a significant increase from last year's report, when just 27 percent of respondents reported these attacks.

DDoS Attacks GrowAs for application-layer attacks, 86 percent of respondents reported experiencing those kinds of attacks. According to Arbor, the proportion of reported application-layer attacks has not changed much during the last few years for most services such as HTTP, DNS and SMTP. The only clear change the company found was in relation to HTTPS, with 37 percent of the respondents seeing application-layer attacks targeting this service compared to 24 percent last year.

"There is a very clear trend we see in the increased use of complex multi-vector and application layer attacks," said Gary Sockrider, solutions architect for the Americas for Arbor. "These methods are inherently more difficult to defend against and also more difficult to detect. In disguising the attacks as web traffic (HTTP) and even encrypting them (HTTPS) the malicious traffic attempts to hide by mixing in with legitimate traffic destined for the victim."

This year's survey also found an increase level of concern regarding compromised machines on provider networks, with 61 percent naming botted computers as a top concern.

"The increase in botted hosts is not surprising given the number and complexity of malware variants that exist, their rate of evolution and the consequent inability of Intrusion Detection Systems (IDS) and Anti-Virus (AV) systems to fully protect them," according to the report. "Looking ahead, there is even more concern about APT, industrial espionage, data exfiltration and malicious insiders."

There has been a substantial increase in the proportion of respondents using Intelligence DDoS Mitigation Systems (IDMS) to mitigate attacks, which has jumped to 60 percent from 45 percent.  However, 78 percent of respondents indicated that their organization has dedicated operational security resources, a decrease from last year.  

"The most surprising thing that I saw was the reduction in dedicated security resources among respondent organizations," Sockrider said. "This is further explained by the next question we asked. The key challenges facing respondents when building and maintaining an effective operational security team were a "lack of headcount and resources" and "difficulty in finding and retaining skilled personnel." However, lack of both operating expense budget and capital funding were cited as issues by more of our respondents than in previous years, potentially indicating that cost reductions within network operations have had an impact here."