FREDERICK, Md. (WDVM) — Have you ever purchased an android phone online from an outlet that wasn’t a known service provider? Cyber officials are telling users to watch out for malware.

Cell phones can be purchased in-store or online. Android users need to be aware when they want a new phone. Phones you purchase online can already be infected with malware, specifically purchases that are not from major android partners.

“The phone maker doesn’t even know that there is malware on the phone, agreed to allow some third party software developer to provide software onto the phone that they are selling,” Darren Clark said, owner of Clark Computer Services.

Androids operating system is open source and allows for more affordable phones. But being an open source gives hackers the ability to sneak in prepackaged malware. Officials say preinstalled malware has been discovered on more than 7.4 million android devices. “Anybody is allowed to use the android operating system to make their own phone,” Clark said.

Since applications that have malware are approved and installed by the phone maker, antivirus programs can’t flag them as being harmful. “There is nothing that would even give you an indication that its infected which is what makes it very dangerous, the security software you put on there doesn’t pick up because that software is trusted by the phone itself,” Clark said.

Cyber officials suggest only purchasing android phones that have been certified by Google who owns Android. Officials also say preinstalled malware is not a high concern for Apple IOS users or the App Store.