Arbor Networks' Third Annual Worldwide Infrastructure Security Report highlights botnets and the increased size of distributed denial of service (DDoS) attacks as a growing threat to ISPs.
For the first time, botnets surpassed DDoS attacks as the top threat identified by service providers.
Arbor Networks says it has security customer relationships with more than 70% of the global service provider community, which enabled it to gather input from 70 tier-1, tier-2 and hybrid IP network operators in North America, Europe and Asia for the report.
The report covers the 12-month period from July 2006 through to June 2007.
This year, a much larger percentage of the respondent pool believed bots and botnets to be a larger threat than DDoS attacks. Bots are PCs remotely taken over by hackers without the knowledge of their owners and are usually linked together to form botnets to spread malware and spam.
The threat of DDoS attacks still looms large for ISPs though. Although mid-level DDoS attacks have plagued the internet since 2000, survey respondents reported a widening gap between common mid-level "amateur"
attacks and multi-gigabit "professional" efforts involving tens of thousands of bot hosts.
Most surveyed ISPs reported significant improvements in the sophistication and coordination of DDoS attacks.
In addition, says the report, voice over IP services are vulnerable with a lack of security protection across ISPs. The report found that only 20% of ISPs currently have specific tools or mechanisms to monitor and detect threats against VoIP services.