If you own some models of smartphones running on the Android operating system, you are more vulnerable to being hacked, researchers at North Carolina State University say.

In a report issued Wednesday, the NCSU team says that features incorporated into the phones to make them more user friendly also increase their vulnerability. Android-equipped smartphones are the world’s most popular.

Five models were found to display “the most vulnerabilities”, NCSU said:

• HTC’s Legend
• HTC’s EVO 4G
• HTC’s Wildfire S
• Motorola Droix X
• Samsung Epic 4G

HTC, which operates a research and development office in Durham, is based in Taiwan and is one of the world’s largest smartphone manufacturers.

NCSU said the manufacturers have been notified about their findings.

“Some of these pre-loaded applications, or features, are designed to make the smartphones more user-friendly, such as features that notify you of missed calls or text messages,” said Dr. Xuxian Jiang, an assistant professor of computer science at NC State who is co-author of a paper about the research. “The problem is that these pre-loaded apps are built on top of the existing Android architecture in such a way as to create potential ‘backdoors’ that can be used to give third-parties direct access to personal information or other phone features.”

The pre-loaded apps are vulnerable due to “backdoors” used by hackers to access phone calls, send text messages to premium sites that adding to a users’ phone bill, and wiping out user settings, Dr. Jiang said.

Eight models in all were tested.

“If you have one of these phones, your best bet to protect yourself moving forward is to make sure you accept security updates from your vendor,” Jiang said of the five most vulernable models. “And avoid installing any apps that you don’t trust completely.”

More phones will be tested, NCSU said.

The National Science Foundation and the U.S. Army Research Office are supporting the group’s work.

Read the full paper here.

Watch a video describing the vulnerabilities here.

Working with Dr. Jiang on the report were NC State Ph.D. students Michael Grace, Yajin Zhou and Zhi Wang.

Get the latest news alerts: Follow WRAL Tech Wire at Twitter.