Many websites use CAPTCHA prompts (those small prompts asking you to confirm you’re not a robot) as a security measure. Unfortunately, malicious actors are now mimicking these prompts in a new method of attack that can compromise your computer with just a few keystrokes.
These fake CAPTCHA attacks are becoming more common and are quite effective because they often appear on websites that users trust, such as news and educational websites. The goal is to trick users into unknowingly run commands that install malicious software.
How the attack works
A user visits a legitimate website that has unknowingly allowed a malicious advertisement to be displayed through a 3rd party ad server. When the ad appears, the user is redirected to a maliciou site displaying a fake CAPTCHA. After a user clicks the CAPTCHA checkbox, a prompt appears asking them to press a combination of keys like WIN+R, CTRL+V and Enter (example below).
These inputs launch a script on the user’s machine that silently downloads and installs malware. Because this attack mimics routine behavior and comes from sites that we normally trust, it can be quite deceptive.
What should you do?
If a CAPTCHA prompt ever asks you to press keyboard shortcuts like WIN+R or CTRL+V, DO NOT follow these instructions. A legitimate CAPTCHA will never require keyboard input beyond clicking a checkbox, selecting images, typing characters or sliding.
If you encounter any unusual prompts or website behavior, report it to technology right away. Quick reporting allows us to take immediate action and helps protect our staff, students, and community from these malicious actors.
In case you were wondering, (Completely Automated Public Turing test to tell Computers and Humans Apart).