Charities and police have warned that computer hackers are able to watch victims through their laptop webcams.
The practice - known as 'Ratting' (for 'Remote Administration Tool') - is a variation of standard virus or malware attacks which have affected computers for decades.
By coaxing users to install malicious software on their computers, hackers are able to access video feeds from any webcam without the user knowing that they're watching.
The phenomenon was detailed in an extensive investigation by Ars Technica earlier this year, and now BBC 5 Live has produced its own report, which includes calls by British police and charities for users to be more vigilant.
The BBC report quotes Rachel Hyndman, a 20-year-old student who says hackers may have watched her while she watched a DVD in the bath. She says her webcam was switched on without her knowledge while the computer was (presumably) safely placed away from the water.
Hyndman said in the report: "I was sitting in the bath, trying to relax, and suddenly someone potentially has access to me in this incredibly private moment and it's horrifying.
"To have it happen to you without your consent is horribly violating."
The BBC report also detailed how access to compromised computers is bought and sold online - $1 for a woman's webcam, or a single cent for access to a man's machine - and also quotes a hacker who said he did it for a "laugh".
He told the BBC:
"The risk of getting caught, that someone would do something about you trolling people, isn't that much. It's just a bit of a laugh"
Chief executive of Childnet International Will Gardner said that while such attacks may not be "commonplace", they do happen - and that computer users should learn to take precautions. Those include installing anti-virus software and even covering up a webcam when not in use.
An Association of Chief Police Officers representative told the BBC that accessing webcams without permission is illegal, and would be prosecuted wherever possible.