Rihanna Attempted Burglary -- Suspects Caught On Tape

Rihanna's string of bad luck with homes continues -- someone tried to break into her Pacific Palisades mansion over the weekend ... TMZ has learned.

While Rihanna gallivanted around Australia half-naked ... someone drove up her private road onto her $12 million property, walked to the backyard and threw a chair through a sliding glass door ... law enforcement sources tell TMZ.

The would-be burglars were scared off -- apparently by the alarm, because they left without entering.

Here's their problem -- Rihanna's house is covered by security cameras. And get this ... to approach the property you have to drive onto a private road. As you turn onto the road, there's a sign: "Smile, You're on camera"

Cops are still on the hunt for the intruders.

It's not the first problem Rihanna has had with unwanted visitors. In February a stalker tried to break into her house but mistakenly entered her neighbor's pad ... then in June, another man was busted by her security team, after they spotted him creeping on her roof.

And you may recall ... before buying this estate, Rihanna lived in Bev Hills, where she sued the former owner, home inspector and realtor, claiming they defrauded her by unloading a leaky piece of crap.