The amount of targeted attacks has increased by four times over the course of 2011.
According to Symantec's intelligence report for November, an average of 94 targeted attacks were blocked each day during the month, compared with 25 in January. Put into perspective, one in 255 emails in November contained some form of malware, but only one in 8,300 of these was a highly targeted attack. Symantec determined that overall, one in every two million emails contained a targeted attack.
It said: “With an estimated 48 billion emails in circulation each day, a highly targeted attack of this nature accounts for a very small percentage of email traffic, but they are certainly not as rare as at the end of 2010.
“These attacks all have the potential to seriously impact an organisation, and in the longer term they represent a significant threat against the economic prosperity of many companies.”
Paul Wood, senior intelligence analyst at Symantec.cloud, said: “The aim of these targeted attacks is to establish persistent access to the targeted organisation's network, in many cases with the aim of providing remote access to confidential data.
“Targeted attacks are designed to gather intelligence, steal confidential information or trade secrets and, in the case of attacks like Stuxnet, disrupt operations or even destroy critical infrastructure.”
The report also found that the public sector was the most frequently targeted industry during 2011, with approximately 20.5 targeted attacks blocked each day. The chemical and pharmaceutical industry was second-highest ranked, with 18.6 blocked each day.
Also, organisations with more than 2,500 staff were the most targeted, with 36.7 attacks blocked each day. In contrast, the small- to medium-sized business sector (with fewer than 250 employees) had 11.6 attacks blocked daily.