BlueHammer abuses Windows Defender's update process to gain SYSTEM access
hackingpassion.com
hackingpassion.com
Yeah, I know, karma hit coming, but the other comments are so counter to my experience (I quite like the page and content) that I could not not comment.
:)
It can steal your cookies and browser saved passwords, it can upload your photos or delete them.
Privilege escalation to SYSTEM is the least of your worries.
Ha,ha. Your browser sandbox is executing remote code. And the sandbox is not.