malware??

Adobe Flash downloads are known offenders. Never download it because some pop-up told you to. Always download updates from Official Adobe Website or from System Preferences > Flash Player > Check for updates.

Download and run Malwarebytes. Malwarebytes was developed by one of our own colleagues here in ASC and is about the most proven anti-malware software for Mac.

Almost all websites now use HTML 5 which obviates the need for Flash. You probably do not need it. If not then uninstall it.

You may have to get & use malwarebytes for mac. ~ The free

portion should be adequate to go after the adware & malware.

And that's all I have now, after the trial period expires; a basic

software that still works OK and will see updates after expiry..

The 'premium' portion that works free for 14 days, is good; but

not necessary to renew or buy to have basic protection and fair

removal benefits. Another software that I've found helpful, is

Etrecheck; both these softwares are by fellow mac-users who

have helped in this ASC site for many years.

There are more manual methods that require lots of time, attention

to detail, and knowing what to remove from where; then do DIY.

While I've these two and am careful 'to not download junk' online.

Be very careful with what you click on. You've likely clicked a link or a popup to install Flash Player.

And as Macjack already stated. Flash is unnecessary these days. And that's a good thing as well. Flash is known to be very unsafe.