Gmail's security is being enhanced to keep its users protected from malware, phishing attacks and other threats.

Earlier this week, Google announced that it would begin notifying users about potentially unsafe emails in their inbox that can include unencrypted emails. If a user is in fact about to send a message that doesn't support TLS encryption, Gmail will warn them with a red broken lock icon at the top right corner of the mail.

Gmail will also flag emails from unidentifiable contacts. The recipient will be alerted about emails coming from unauthenticated sources and show a question mark to replace the profile photo of the contact.

Google has also launched Security Checkup, a service that controls the security settings of a Gmail account. It lets users add a recovery phone number, check the devices connected to their account, and make their password stronger.  

“Not all affected email will necessarily be dangerous. But we encourage you to be extra careful about replying to, or clicking on links in messages that you're not sure about,” said John Rae-Grant, product manager at Google.

With new tools and filters, Google also plans to improve protection against ad traffic from botnets. Gerhard Eschelbeck, VP, security and privacy at Google, said: “We've worked to keep botnets out of our ads systems, cutting them out of advertising revenue, and making it harder to make money from distributing malware and unwanted software.”