PUP.Optional.Wajam is the detection name for Wajam, a browser add-on marketed as a “social search.”
PUP.Optional.WinYahoo is a PUP that performs changes on popular browsers installed on affected systems. Particularly, it modifies the user’s default home, start, and search pages for their Chrome, Firefox, Internet Explorer, and Safari browsers. This PUP also performs redirects to unwanted sites.
Furthermore, PUP.Optional.WinYahoo installs browser extensions / add-ons / plug-ins.
This PUP arrives on systems bundled with other software. There are also instances wherein malware could install PUP.Optional.WinYahoo.
Malwarebytes completely removes PUP.Optional.WinYahoo. No further clean up is required.