In a blog post, the company's researchers Bo Qu, Tao Yan, Rongbo Shao and Zhanglin He wrote: "Unit 42 regularly analyses statistical data from our Email Link Analysis to understand the patterns and trends in current Web threats."

As statistics have little meaning unless knows the base they are drawn from, iTWire asked Palo Alto about the research.

"I need one stat: how many emails/links were analysed to obtain this data? I presume these were all from customers of Palo Alto. Some indication of the sample size is needed to give veracity to the data," was the query sent to the company.

Security firms normally base their conclusions regarding malware, exploits kits and the like on data that they collect from their own customers.

Regarding the Email Link Analysis mentioned, the company has this explanation on its site: "A Palo Alto Networks firewall can extract HTTP/HTTPS links contained in SMTP and POP3 email messages and forward the links for WildFire analysis.

"The firewall only extracts links and associated session information (sender, recipient, and subject) from email messages; it does not receive, store, forward, or view the email message."