Many companies let workers monitor and manage machines—and sometimes entire industrial processes—via mobile apps. The apps promise efficiency gains, but they also create targets for cyberattacks. At worst, hackers could exploit the flaws to destroy machines—and potentially entire factories.

Two security researchers, Alexander Bolshev of IOActive and Ivan Yushkevich of Embedi, spent last year examining 34 apps from companies including Siemens and Schneider Electric. They found a total of 147 security holes in the apps, which were chosen at random from the Google Play Store. Bolshev declined to say which companies were the worst offenders or reveal the flaws in specific apps, but he said only two of the 34 had none at all.

Some of the vulnerabilities the researchers discovered would allow hackers to interfere with data flowing between an app and the machine or process it’s linked to. So an engineer could be tricked into thinking that, say, a machine is running at a safe temperature when in fact it’s overheating. Another flaw would let attackers insert malicious code on a mobile device so that it issues rogue commands to servers controlling many machines. It’s not hard to imagine this causing mayhem on an assembly line or explosions in an oil refinery.

Bolshev says this combination of apps and industrial control systems is “a very dangerous and vulnerable cocktail,” though he stresses that the risk will vary widely. Some companies may have multiple fail-safe systems that limit potential damage. They may also insist that engineers rely on several data sources for a machine rather a single reading from an app.

That’s not totally reassuring, however, because there’s evidence hackers have already been able to evade broader defenses around manufacturing facilities (see “A New Industrial Hack Highlights the Cyber Holes in Our Infrastructure”). And the risks extend to other areas; power plants and transport systems are also being hooked up to the Internet. Mobile apps could prove weak points here too.