Rubicon Project Cookie

Hello friends from Symantec! Hope everything goes just fine!

A few weeks ago I received some alerts from Microsoft and a couple of accounts were blocked because some kind of suspicious software was triying to send emails in a massive way. When I run the full scan in the infected computers all of them had the same cookie advise like this one: pixel-us-east.rubiconproject.com/exchange/ 

I want to know if someone have seen something like that before or if its dangerous. 

Thank you so much!!