A new feature added in the recent Gmail redesign could present an 'emerging threat' to users, US intelligence officials have warned.
The new feature, known as 'Confidential Mode', could leave an increased number of users susceptible to attacks from cybercriminals.
The Department of Homeland Security (DHS) circulated an intelligence note to US law enforcement, as well as government cybersecurity workers, reports dailymail.co.uk.
'Confidential Mode' allows users to set an expiry date on sensitive emails and add two-factor authentication to their communication.
However, this requires users to click a link in order to access sensitive emails.
DHS agents cautioned that hackers pretending to be someone else to gain access to users' personal information are likely to send-out mass scam messages containing fraudulent versions of these confidential links.
US officials said the new tool presents a 'potential emerging threat ... for nefarious activity', adding that all of Gmail's 1.4 billion users worldwide are at risk.
"We have reached out to Google to inform them of intelligence relevant to their services and to partner to improve our mutual interests in cybersecurity," DHS spokesperson Lesley Fulop was quoted by express.co.uk.
If you're a Gmail user using the official Google Mail website then the "Confidential Email" appears when you click to open it. It shows a date for when the content will expire and informs the users that the email can't be forwarded or downloaded.
However, it’s different if you're a Gmail user viewing the message as a third-party client or a non-Gmail user who receives a confidential email.
In those cases, instead of the message appearing in their browser, users have to click a button to view the email. And this is where the security fears lie.
With the Gmail redesign, scammers could send out fake versions of confidential email alerts and trick a user into entering sensitive details.
"The tech giant is committed to protecting the security of users' personal information and hence, had created "machine learning" algorithms to detect potential phishing scams that cybercriminals carry out," said Google spokesman Brooks Hocog.
Phishing scams are where cybercriminals try to trick victims into clicking on seemingly trustworthy links in order to steal sensitive personal information.