Between 50 and 70 percent of the incoming emails processed by Gmail in a given day are spam, but only about one out of every thousand messages that actually reach users meet the same criteria. This is thanks to sophisticated filtering algorithms that the search giant made public today alongside several other security enhancements.

The first is an improved version of the malware scanner that Google Inc. uses to identify threats lurking in email attachments. According to the company, the mechanism now takes a much wide range of factors into account when assessing a file, including whether or not it’s sent from a domain with a history of triggering spam filters. The result is that it’s better equipped to identify undiscovered “zero-day” exploits and other advanced threats that might go undetected if inspected in isolation.

The new malware detector is complemented by an anti-phishing feature aimed at scenarios where the default security vetting may not be enough. If an organization chooses to enable the option, Google’s algorithms will delay suspect emails and run them through an exhaustive vetting process that can take up to four minutes. The search giant detailed that its algorithms check both the contents of each message and any websites to which it might link. 

The latter step is performed using data from the company’s Safe Browsing Service, which is responsible for the threat warnings that show up in Chrome when a user opens a suspicious website. The tool is one of the most reliable in the category thanks to Google’s deep visibility into the online landscape.

Rounding out the security enhancements is a feature designed to prevent data leaks of the accidental kind. When users replies to email from someone whose account isn’t tied to their company’s domain name, Gmail will now display a warning asking them to be careful about sharing sensitive information. It’s designed to reduce the privacy risks posed by human error and hackers who deliberately try to trick users with deceptive domains.

Because many professionals interact with people outside their firms on a regular basis, this feature is turned off by default. Administrators can enable it in the G Suite management console.

Image: Google