Unmasking the Viral Evolution of the ClickFix Browser-Based Threat guard.io/labs/capt…

What began as a niche red-team trick posing as a harmless captcha challenge rapidly mutated into one of today’s most dominant attack methods. Like a real-world virus variant, this new “ClickFix” strain quickly outpaced and ultimately wiped out the infamous fake browser update scam that plagued the web just last year. It did so by removing the need for file downloads, using smarter social engineering tactics, and spreading through trusted infrastructure. The result - a wave of infections ranging from mass drive-by attacks to hyper-targeted spear-phishing lures.

In this article, we unpack how the fake captcha attack evolved so quickly across three critical dimensions: propagation methods, narrative sophistication, and evasion techniques. We showcase wild samples and novel payload delivery tricks and share a unique clustering method that helped us trace how multiple threat actors are adopting and evolving this new weapon, each shaping their own flavor of CAPTCHAgeddon.