The size of cyber attacks that aim to overwhelm websites with massive amounts of traffic exploded in the first quarter, with the bandwidth of an average attack skyrocketing 691%, a new report released on Wednesday reveals.

The quarterly data on distributed denial of service (DDoS) attacks underscores the increased challenges facing companies like banks, media outlets and retailers that rely on their website staying online.

According to DDoS protection services provider Prolexic Technologies, the average attack bandwidth surged to 48.25 gigabytes per second in the first quarter, representing a 691% increase from the year before and a 718% rise from the fourth quarter of 2012.

“Never before have attacks been this formidable,” Prolexic said in the report.

Moreover, Prolexic said more than 10% of attacks against its client base averaged more than 60 gigabytes per second. One attack, against an unnamed enterprise customer in March, peaked at 130 gigabytes per second.

Attacks are also growing in duration, jumping an average of 21% year-over-year to 34.5 hours, the report said.

Likewise, DDoS attacks are happening more frequently, climbing 21.75% from the first quarter of 2012. March alone accounted for 44% of the first quarter’s attacks, Prolexic said.

“When you have average -- not peak -- rates in excess of 45 Gbps and 30 million packets-per-second, even the largest enterprises, carriers, and quite frankly most mitigation providers, are going to face significant challenges,” Stuart Scholly, president of Prolexic, said in a statement.

The alarming report comes as a slew of big-name companies have acknowledged cyber attacks in recent months, including Apple (AAPL), Facebook (FB), The New York Times Co. (NYT) and Wells Fargo (WFC).

A high-profile attack revealed last quarter by The New York Times led the paper to point the finger at China.

While some analysts have expressed skepticism about being able to trace the origins of an attack, Prolexic said 40.68% of DDoS attacks in the first quarter were believed to be from China, compared with 30.59% in the year-earlier quarter and 55.44% in the fourth quarter of 2012.

At 21.88%, the U.S. ranked second in the first quarter, up from 19.20% the year before and just 2.71% in the fourth quarter.

The next highest source countries were Germany (10.59%), Iran (5.51%) and India (5.01%).

In addition to DDoS attacks that slow down or even block access to websites, companies are also grappling with cyber espionage attacks that can lead to the loss of valuable intellectual property like secret formulas or tip off adversaries about strategic plans.

 

Follow Matt Egan on Twitter @MattMEgan5