MI5 has warned foreign spies are using LinkedIn to contact British officials and get them to share secrets.
Security chiefs say at least 10,000 UK nationals across government departments and key industries have been approached over the past five years by fake profiles.
The false accounts are linked to hostile states, according to British spooks.
Spy agency MI5 has now launched a campaign, called Think Before You Link, to alert government ad public sector workers to the threat.
The initiative warns people with access to sensitive information are being targeted, the BBC reported.
The security agency’s boss, Ken McCallum, said: “Malicious profiles on professional networking sites are being utilised on an industrial scale.”
Hostile states, such as China and Russia, have used social media websites to link to Brits working in government areas in recent news, Sky News reported.
These reportedly include UK defence contractors, civil servants and military and security officials.
They are said to offer money, business opportunities and conference fees to those who have access to classified information.
Dominic Fortescue, government chief security officer, said: “Since the start of the pandemic, many of us have been working remotely and having to spend more time at home on our personal devices.
Want all the latest shocking news and views from all over the world straight into your inbox?
We've got the best royal scoops, crime dramas and breaking stories - all delivered in that Daily Star style you love.
Our great newsletters will give you all you need to know, from hard news to that bit of glamour you need every day. They'll drop straight into your inbox and you can unsubscribe whenever you like.
You can sign up here - you won't regret it...
"As a result, staff have become more vulnerable to malicious approaches from hostile security services and criminal organisations on social media."
The campaign is being run by the Centre for the Protection of National Infrastructure.
Similar programmes have been launched in the US and other countries.
LinkedIn has said it welcomes the move.
In a post, the professional networking site said: “We actively seek out signs of state sponsored activity on the platform and quickly take action against bad actors in order to protect our members.
“Our Threat Intelligence team removes fake accounts using information we uncover and intelligence from a variety of sources, including government agencies.
“And we enforce our policies, which are very clear: fraudulent activity with an intent to mislead or lie to our members is a violation of our terms of service.”