Jailbreaking an iPhone has long been viewed as a big security no-no. But new malware discovered by security firm Palo Alto Networks has put a finer point on why jailbreaking your iPhone could leave you — and your personal information — in the crosshairs of malicious hackers.

Jailbreaking is the practice of using software to remove hardware restrictions on an iPhone, iPad or any other iOS device. The process is not for the faint-of-heart and can potentially “brick,” or render useless, the device before it’s even successfully jailbroken. And if you're iPhone is bricked, it's no longer covered under Apple’s warranty.

Still, for some, those risks are worth the reward. By jailbreaking an iOS device, you can gain access to third-party application stores to download apps not found in Apple’s App Store.

Related: How to Keep Apps from Learning Too Much About You

But here's a reason to reconsider jailbreaking your Apple device. Jailbreaking provides root access to iOS, effectively allowing any malware (malicious software) that reaches the product to do whatever it wants, whenever it wants. 

The latest — and largest — malware hack

Palo Alto Networks analyzed iOS devices and recently discovered a new malware known as KeyRaider. According to the security company, it’s the “largest known Apple account theft caused by malware” in history, affecting users from 18 countries including China, France, Russia, Japan, United Kingdom, United States, Canada, Germany, Australia, Israel, Italy, Spain, Singapore and South Korea.

KeyRaider’s plan for iOS devices is rather simple: The software gains access through third-party app stores, installs malware and quickly accesses your iTunes App Store account information. From there, the malware can make purchases from the App Store, charge your account and give hackers access to whatever they want. The hackers also built in a method for blocking you from being able to access your device.

Related: Data Hacking Victim? Why and How to Monitor Your Credit Reports

So far, according to Palo Alto Networks, KeyRaider has stolen more than 225,000 Apple accounts. But there’s one caveat that shouldn’t be overlooked: It affects only people who have jailbroken their devices. If you didn’t jailbreak your phone, you won't fall victim to this attack.

If you did jailbreak your iPhone, to find out if you’re a victim, check your app purchase history and make sure there are no suspicious purchases.

This latest hack demonstrates why jailbreaking is risky. While it may open you to a world of new apps, it also opens you (and your personal data) to a world of vulnerability.

Related: 4 Places Never to Keep Your Cell Phone

Don Reisinger is a longtime technology journalist and product reviewer.