Some of the world鈥檚 most popular internet sites suffered blackouts on Tuesday following a co-ordinated and distributed online attack.
Google, Yahoo, Microsoft and several other major sites faltered as a result of the attack, which started at 10:45 EST on Tuesday and lasted for over two hours. The problems were traced to Akamai, in Massachusetts, US, which provides support to the internet giants though a vast network of distributed servers for all of the sites.
Technical experts said the incident was consistent with an attack on its domain name system (DNS) servers. These servers translate web browser requests for a worded domain name into the numerical information used to route packets of data around the internet.
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Akamai confirmed that its servers were affected by 鈥渓arge-scale, international attack on internet infrastructure鈥�. But the company suggests the attack was actually directed at a number of its customers, and had a knock-back impact on its distributed servers.
Tidal wave
The incident struck several of Akamai鈥檚 1100 customers, including Apple and anti-virus companies Symantec and TrendMicro. Many of the affected web sites are used to provide customers with automatic software updates.
Although Akamai declined to provide details of the attack, its comments suggest it was a distributed denial of service (DDoS) strike. This involves using an army of remote controlled computers to bombard a server with a tidal wave of fake traffic, to make it inaccessible to normal customers.
Hackers take control of these computers using automated software tools or computer viruses to exploit software vulnerable. The trick is particularly difficult to defend against because the traffic appears to be genuine and comes from all sides at once.
Akamai has more than 15,000 machines distributed in 65 countries around the world, forming what the company claims is the largest distributed computing network anywhere.
Brute force
These distributed machines periodically copy the web sites they are programmed to support, and when access to one of these sites problematic, provide localised backup.
As Akamai鈥檚 network is designed specifically to cope with extra demand, the attack must have been very large, says Richard Miller, an analyst with UK-based internet monitoring company Netcraft.
鈥淚t鈥檚 worrying if someone has a zombie network that can overwhelm a system like Akamai鈥檚,鈥� Miller told 快猫短视频. 鈥淏ut we don鈥檛 know if it was just brute force or whether someone has found a specific weakness.鈥�
Lloyd Taylor, vice president of technology at Keynote, a US company that monitors the availability of internet sites, told Reuters that the many sites were virtually unreachable during the assault. 鈥淭he availability issues were limited to several large sites, all of whom outsource their domain name server (DNS) services to Akamai,鈥� Taylor said. 鈥淭hese sites dropped to near-zero availability.鈥�
Similar disruption to Akamai鈥檚 distributed network occurred on 24 May. This also affected the availability of many prominent websites but was the result of technical problems rather than an attack.
