A new research paper warned of phishing threats in which malicious actors abuse trusted web services to evade detection.

According to the report by Cofense, fraudsters are getting creative in their efforts to make sure their emails make it through email gateways and firewalls. Specifically, threat actors are using web services such as Google Drive, SharePoint, Dropbox and others to host files containing embedded links that redirect to credential-stealing websites.

Email Remains a Top Attack Vector

Many common email gateways are unable to detect and block the malicious links included within those files. Some perform better when the body of the email contains a malicious link to a phishing page. However, Cofense found several instances in which those gateways failed to rewrite a malicious URL completely, which allowed the attack email to get through. The security firm also noted one instance in which an email security platform successfully rewrote a URL but failed to block it.

This is particularly concerning because email is one of the most popular attack vectors in use today. Verizon recorded 1,192 email phishing incidents over the course of the year in its “2018 Data Breach Investigations Report,” and a Symantec survey found that 1 in 9 users encountered email malware during the first half of 2017. This made users twice as likely to encounter malware through email than through exploit kits. By the end of 2017, Symantec observed that the number of malware-laden emails received by users had nearly doubled in six months to 16.

How to Protect Against Phishing Attacks

Security professionals can protect their organizations against phishing attacks by conducting a simulated phishing engagement to test the organization’s incident response processes. They should also adopt a layered approach to email security that includes perimeter protection, email security solutions and cyber awareness training for all employees.

Sources: Cofense, Verizon Enterprise, Symantec, Symantec[1]