Nearly half of users are unnecessarily vulnerable to attack, with just 54 per cent of users able to pass a basic mobile device security test.
Almost half of UK mobile users are dimwits when it comes to security.
A study from knowthenet.org.uk has found that 46 per cent of people cannot pass a simple mobile security test.
The survey shows that 27 per cent of people aren't aware that they need to protect their mobiles, 31 per cent don't know how to, and 19 per cent don't even think it's necessary.
Other worrying results include:
21 per cent of 16-24 year-olds have been phonejacked
17 per cent have clicked on unknown links sent to their devices
19 per cent are happy to log on to unencrypted wi-fi connection
In the UK, 120,000 smartphone are stolen each year, highlighting the importance of making sure yours is secure should the worst happen.
Phil Kingsland, site director at knowthenet.org.uk, said: "The prevalence of mobile devices is making them a target for cybercrime. The personal and sensitive information stored on the devices, their portable nature and a failure to view them as a target for crime means users in the UK are now vulnerable to device fraud and security lapses.”
Take the test at http://inthedark.knowthenet.org.uk