If it turns out to be adware you can remove it with the only other third-party utility (other than EtreCheck) most of us trust: MalwareBytes.
It was developed by one of our most respected and long-server contributors here to effectively screen for and remove adware that gets installed because a user either does not see or does not heed OSX warnings about potential malware about to be installed. Unlike most utilties it DOES NOT interfere with protection schemes already built into Mac OS.
I trust it NOT to remove something important. Get it only from the developer's site: https://www.malwarebytes.com
The free version scans manually and should be fine your current situation. The pay-for version adds real-time protection.