A distributed-denial-of-service (DDoS) attack targeted several major retail websites late Wednesday, crippling parts of the sites for about an hour during the last minute holiday shopping rush.
People trying to shop on Amazon, Wal-Mart and Gap, as well as users of Salesforce.com and popular travel site Expedia experienced general sluggishness and outages as a result of the flood of malicious traffic directed at UltraDNS, a registrar service that resolves the high profile website addresses.
Wednesday night, officials at Neustar Inc.’s UltraDNS said outages had the most impact on the West Coast.
In a message on Twitter, Jeff Barr of Amazon Web Services said the outages were limited and affected mainly Northern California. The attack also briefly affected Amazon’s S3 and EC2 services as well. All of Amazon’s web services were functioning normally Thursday morning.
Service providers typically act quickly to resolve DDoS attacks. Most attacks are fairly standard and easy to mitigate, experts say. Using proactive defenses, including automated sensors and blocking techniques, administrators at UltraDNS and other DNS services can detect patterns and funnel them out, quickly limiting their impact.
In July, DDoS attacks, some say may have originated in North Korea, targeted the domains of some U.S. and South Korean government websites. Experts called the DDoS attacks unsophisticated and said they had little to no impact on day to day business.