Your mobile device contains plenty of personal information and if you are unfortunate enough to pick up some malware while using it, well that can result in plenty of problems. Hackers can gain control of tablets and iPhones via several methods, to copy data, steal credentials and your financial information. Picking up the wrong kind of malware can also mean that hackers can watch your every move online while you use your mobile device, here are some tell tale signs.

Because mobile devices usually contain a large amount of apps it makes your mobile device vulnerable to hacking and puts your information at risk. While many of us rely on our tablets for social media, games and navigation, we also tend to store vital data in our devices and be completely oblivious to the data they are gathering.

Hackers can gain control these devices, running botnets to copy vital information—then compromising the device owner’s security. To secure your mobile device from hackers, you’ll first need to know what they’re after—then, you’ll need to look for the telltale signs of malicious attempts on your device.

Below, we’ll cover the top telltale signs of device hacking—assuring your software glitches acquire the attention they deserve.

Warning Sign One: Extreme Battery Usage

If you need to charge your battery frequently, it means your device is running numerous background processes. Sometimes, this is a simple case of an excessive number of downloaded mobile apps. Sometimes, however, it can mean your device has malware on it.

Depending on the type of downloaded malware, you could become the victim of document theft—or even identity theft. If your iPhone’s battery heats up to unnatural degrees, it might have battery issues as well—resulting in the detection of malware. Or, it could simply mean your battery isn’t strong enough due to your iPhone’s age.

To avoid malware on your phone, avoid using social media apps too often. It’s a good idea to avoid playing too many games on your iPhone, too. These portals are common spyware targets, causing batteries to drain rapidly.

Warning Sign Two: White Noise During Phone Calls

If you’ve experienced a high degree of background ‘white’ noise during phone calls, or even when listening to audio on your phone, it might mean someone is intruding on your conversations. It could even mean someone is currently trying to enter your phone: The white noise is associated with hardware and software glitches occurring in the background.

Keep tabs on your phone’s usage, and make sure you’re taking note of any malfunctions it’s currently experiencing. It’s also a good idea to check for regular updates, and to treat any glitches as potential hacking attempts.

Warning Sign Three: Data Usage

A good way to secure your iPhone from hackers is to keep an eye out for data usage. Many of us delegate our data usage per month, keeping our phone bills low while completing—more or less—the same tasks on a week-to-week basis.

If your data usage has suddenly spiked, or if your iPhone bill reports more data use than regular allowance, it might mean your phone has been compromised by malware. It can also mean your device is sending data to places unknown.

Thus, it’s a good idea to delete any apps you’ve downloaded just before the problem has started. Contact your iPhone service provider, soon after. Then, do a full reset of your phone. More often than not, a full restore is required to completely purge traces of malware.

Warning Sign Four: Unknown Emails

‘Phishing’ emails, or emails wherein a hacker pretends to be a trusted entity to garner personal details, are both a varied and successful hacking tool. Phishing emails can be difficult to detect, but they’re incredibly dangerous when they’ve infected iPhones with vital information.

It’s possible to detect these emails, however. Content with typos, excessive grammar errors or even the overuse of punctuation marks throughout the content can indicate a phishing scheme. Impersonal introductions, email addresses and contact from airlines, cruise lines and banks can also be signs of fraudulence. Make sure your only contact with these entities is conducted through secure, official, channels.

It’s also possible your iPhone has come into contact with an embedded email, strange attachments or false web links. If an email looks suspicious, don’t open it. It’s also a good idea to avoid any financial request from a bank or credit union attached to a sudden deadline.

Warning Sign Five: Texts You’ve Never Sent

When an iPhone is hijacked, it might send out false messages via SMS or social media. If these messages are linked with malware, the malware can be installed on the recipient’s phone. If you believe your phone has been the target of such an attack, double-check with your friends and family about possibly unsent texts or Facebook messages.

Even if you haven’t used your phone to contact these people, someone else may have. These malware and general hacking schemes thrive upon the spread of malicious content to as many people as possible. Even a single unauthorized communication attempt can reveal deeper system issues—issues which can quickly become financial problems stemming from seemingly benign mishaps on Facebook Messenger and text messages.

Warning Sign Six: Bluetooth Services are Enabled

Sometimes, malware will turn on Bluetooth services to gain remote access to your devices—or even others. Still, this sign can be difficult to catch. In most cases, the Bluetooth activity will occur before the connection is turned off. As such, it’s important to check your devices often if you believe you’re currently experiencing a malware attack.

Warning Sign Seven: Unexpected Device Changes

From unexplainable iPhone brightness changes to reboots, mysterious hardware changes can signal a hacking attempt—or even persistent spyware. A compromised device will act oddly, resulting in strange spikes of activity in seemingly unrelated ways.

In extreme cases, a successful hacking attempt can even result in unauthorized credit card purchases. Such actions can even circumvent fraud protection, resulting in serious issues with various banking institutions. If your bank has blocked a transaction, it’s well-worth checking your phone for deeper issues—as some malware can stay attached to a device for many years.

Stay safe out there!