Security researchers discovered that 1 in 7 organizations were hit with lateral phishing attacks over a seven-month period.

As Bleeping Computer reported, the study, which was conducted by the University of San Diego, the University of Berkeley and Barracuda Networks, analyzed the results of 180 campaigns that used the technique in which cybercriminals sent phishing messages from compromised internal corporate email accounts.

The results showed that, over the seven-month period, 42 percent of incidents were not even reported to IT departments. This could help explain why 11 percent of organizations affected by lateral phishing campaigns had additional employee accounts compromised.

Working With Addresses Employees Trust

While those behind traditional phishing campaigns sometimes go to great lengths to impersonate banks or other third parties, lateral attacks could pose an even greater risk because employees see messages coming from a known sender.

In 63 percent of cases analyzed by the study, the content of the messages used commonplace phrases such as “shared document” or “account error.” However, the researchers noted that rogue actors weren’t relying on the email addresses alone to dupe victims. For example, 37 percent tailored the message content to the target victim, or at least used language that would be relevant to an enterprise audience.

Rather than simply sending a one-time message as a lure, meanwhile, the study found one-third of lateral attacks erased phishing messages from the compromised account or responded to questions from the recipient to be even more convincing.

No matter the approach, more than half of lateral attacks (55 percent) were deliberately aimed at those with a work or personal connection to the company that owned the compromised account. Almost all such phishing campaigns were run during normal working hours, the research report’s authors added.

On the other hand, researchers said 45 percent of lateral attacks didn’t make use of relationships between the owner of a compromised account and those they might know directly. Instead, 29 percent of the phishing campaigns studied simply drew upon recent or close contacts.

Reduce the Risk of Lateral Phishing Attacks

While lateral phishing attacks have some built-in advantages for cybercriminals, organizations that use perimeter protection and security information and event management (SIEM) as part of a layered security approach have a better chance of protecting their data.

This should be coupled with ongoing employee awareness training to ensure employees understand that not all phishing messages will come from spoofed addresses, but also senders that look all too familiar.

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