The spam-blocking technology in Gmail is fairly effective, but that doesn’t mean spammers and criminals don’t want to use Gmail to send dubious messages. A blog post from Google notes a dramatic increase in attempts to hijack individual accounts.
“We’ve seen a single attacker using stolen passwords to attempt to break into a million different Google accounts every single day, for weeks at a time,” Google security engineer Mike Hearn wrote in the post. “A different gang attempted sign-ins at a rate of more than 100 accounts per second.”