Authorize.net, a US provider of online payments processing services, is struggling to remain online after being repeatedly hit by distributed denial of service attacks.
According to press reports, Authorize.net has been pounded by malicious online attacks since last week. Glen Zimmerman, a spokesman for Authorize.net's parent company Lightbridge, told the Boston Globe that the company had received an extortion letter from hackers and was now working with law enforcement agencies to track the attackers.
In a statement Authorize.Net says it continues to experience intermittent distributed denial of service attacks, adding that its system engineers have minimised the impact of each attack and have restored services to affected merchants.
The firm says its is working with industry experts to restore and maintain the transaction processing service.
UK-based online merchant payments operator WorldPay was hit by a malicious denial of service attack last November when vandals bombarded its payments and administration networks with computer-generated requests.