“FOR HACKERS, SCANNING for an open ‘port’—a responsive, potentially vulnerable internet connection on a potential victim’s machine—has long been one of the most basic ways to gain a foothold in a target company or agency. As it turns out, thanks to a few popular but rarely studied apps, plenty of smartphones have open ports, too. And those little-considered connections can just as easily give hackers access to tens of millions of Android devices.”
Source: An Obscure App Flaw Creates Backdoors In Millions of Smartphones | WIRED