WP hijacked by ad popups

Hi,

I just installed WordPress 4 and upgraded to the latest version. when I open the site on a browser, other tabs immediately open with spam advertising from the following sites:

content.getbinary.com
binaryprofessional.com
g49.germanbankersecrets.org

does anyone know how this would happen on a brand-new site… or what PHP pages are likely to have hacker code inserted?

I am using a theme called “Oxygen”

thanks