Yes, that is true, two of my bbpres sites have been injected with the same malicious pop up and after the removal of the sweet captacha plugin everything stopped.
Sweet capthca decided to pass to the black hat and to the dark side of the web.
l got crazy for more than a month now untill today.
After reading the sucuri blog post l understood what happened.
https://blog.sucuri.net/2015/06/sweetcaptcha-service-used-to-distribute-adware.html
Sweet captcha is blacklisted from my wordpress sites for now and forever.
Thank you sucuri!
