Disabling Adobe Flash
Adobe Flash is one of the most exploited pieces of software today; animated banner ads and targeted infections have cost millions of dollars in cleanup and lost productivity. In Firefox, it's not necessary to completely remove Adobe Flash; it's enough just to set it to click-to-activate, where Flash is only turned on when you want it. Once turned on, you won't need to activate it again until you close your browser. In other browsers, it has to be completely enabled or disabled, though Chrome has a whitelist.
Visit CodeGeek's test page to test whether Flash is allowed to run.
Open the main menu, and click on Add-Ons.
Click Plugins on the left, look for Shockwave Flash, and change its setting from "Always Activate" to "Click to Activate."
Chrome removed their click-to-activate feature in favor of automatically loading Flash but requiring a click to unpause, making it a literal "click-to-play." This does not provide protection from malware, only from annoyance. For protection, you have to completely disable Flash.
Edge currently only lets you enable or disable Flash, but a click-to-activate feature is coming later this year, and will be enabled by default.
Ad and Malware Blocking
uBlock Origin is the newest, fastest, and smallest ad-blocker available for most browsers. It not only makes browsing faster and more pleasant, it prevents a range of malware infections. Best of all, it's copletely free!
To install it in your browser, get the latest version.
Bitdefender Total Security
For a full-system defense in depth, check out our page on Bitdefender.