Phishing attacks are nothing new, but they are increasingly used by attackers as a way to exploit a vulnerability common to all businesses: their employees.
In a study released Nov. 4, security-training firm ThreatSim found that an average of 18 percent of messages in a phishing campaign successfully induced recipients to click on a malicious link. One extremely successful campaign induced 72 percent of users to click on the link, according to the report, which was based on the company's anonymized customer data.
Training does help but is not a panacea, according to ThreatSim. Companies that trained their employees at least monthly cut their click-through rate to 2 percent, far lower than the 19 percent for companies that trained quarterly, according to the report.
"Phishing education should be part of an overall program," Jeff LoSapio, CEO of ThreatSim, said in an email interview. "The goal of security awareness training is to make 'security-minded' users and change user behaviors that expose the organization to risk. Phishing is currently one of the top areas in which users can have a direct, near-daily impact on the organization's security."
Phishing has become a key component of many types of targeted attacks. Online thieves use phishing to get access to the computers used for accounting, while more advanced attackers use more targeted phishing, known as spearphishing, to infect a recipient's computer and use that system as a beachhead into the network.
The actual message content, known as the lure in phishing circles, makes all the difference for a convincing phishing attack. Messages that attempt to convince the user that they won something—"Microsoft lottery winner"—are less effective than those that use the specter of loss—"Thanks for your $500 purchase at Amazon."
In addition, targeted attacks, such as a fake employee discount using the worker's company name, are more effective than more general lures. More than 80 percent of recipients who opened a phishing email clicked on the link.
In addition, most users who click on a phishing link also have a computer with vulnerable versions of popular software. Overall, 71 percent of users were vulnerable to exploitation through a common piece of software, such as Adobe Acrobat, Oracle's Java, Adobe Flash or Microsoft Silverlight, according to ThreatSim's data.
Most companies (57 percent) rated the impact of a phishing attack as "minimal," but investigating and cleaning victims' PCs do consume resources, ThreatSim stated in the report.
"In talking to security managers within our customer base, we often hear just how disruptive even a minimal impact phishing attack can be due to how frequent they occur, the level of IT staff time spent in responding [to do] endpoint forensics, and employee downtime [as they wait for] account reset(s) and system restoration," the report stated.