By Ian Bush

PHILADELPHIA (CBS) — Security experts say Google has a lot more more work to do when it comes to keeping harmful software out of it smartphones and tablets.

The newest version of the Android operating system — 4.2 — is supposed to stand guard over your app installations.

“It basically flags the user if any of these applications are known to be malicious or harmful,” says Derek Halliday, the senior product manager of security at the mobile security firm Lookout.

But Halliday says his firm’s tests and research out of North Carolina State University show the vast majority of malware still makes it on to mobile devices.

He says while Google’s now-standard security tools need improvement, these moves are signs that Google is taking the problem of mobile malware very seriously.

Halliday reminds smartphone and tablet users to protect themselves from mobile web-based threats and to back up contact details and personal data.