New Transparent Phishing Attacks Leverage Cloudflare Worker Serverless Computing

Stu Sjouwerman | Jun 3, 2024

Phishing TechniqueAn increasing number of phishing campaigns from several threat groups are being tracked as they leverage legitimate Cloudflare services as part of account compromise attacks.

Security analysts at Netskope take an expository look at the misuse of Cloudflare services for the purpose of enabling phishing attacks that leverage HTML Smuggling and Transparent Phishing tactics.

We’ve seen HTML Smuggling attacks for several years, including its continued use this year. The new kid on the threat tactic block is Transparent Phishing. This is an adversary-in-the-middle method of phishing, where the attacker creates a server that acts as a proxy server between the authenticating service and the victim.

According to Netskope, analysis has been traced to legitimate cloud service Cloudflare’s Cloudflare Workers, a platform that enables its users to execute serverless functions, including serving web pages to its visitors. Threat actors use Workers to act as that adversary in the middle, capturing the victim’s logon requests, credential submissions, MFA requests, etc.

The only way for organizations to stop such attacks is to rely on users to be vigilant of websites, paying specific attention to the URLs – something emphasized in new-school security awareness training.

With users paying attention, threat actors can use every trick in the book and the still won’t fool a user into thinking an email of a logon is legitimate – thereby rendering an attack powerless.

KnowBe4 empowers your workforce to make smarter security decisions every day. Over 65,000 organizations worldwide trust the KnowBe4 platform to strengthen their security culture and reduce human risk.

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