How to tell if your computer or smartphone is hacked or being watched

“Isn’t something odd with my computer?” We hear this often, and the answer ranges from a completely harmless cause to a real compromise. We will show you the signs that someone has taken over or is watching your device, how to verify it and what to do right away. No scaremongering, just practical steps.

Signs that something is wrong

No single sign has to mean anything. The suspicion grows when several appear at once and suddenly.

On a computer:

• sudden slowdowns and overheating for no obvious reason,
• unknown programs, icons or processes you did not install,
• pop-ups and redirects in the browser,
• a disabled antivirus or firewall that will not turn back on,
• unusual network activity even when you are doing nothing.

On a smartphone:

• a fast-draining battery and overheating even at rest,
• unknown apps you did not install,
• increased background data usage,
• suspicious messages, calls or payments.

Suspicious logins and accounts

The attacker does not have to be in the device, they can be in your account. Watch for:

• logins from unfamiliar places or devices,
• settings changes you did not make (email forwarding, recovery contact),
• sent messages you did not send.

If an account is behaving strangely, it is time to check it. We have a detailed guide in what to do when your account is hacked.

How to verify it

• Check active logins and devices in your account settings (email, social media). Sign out unknown sessions.
• Go through the list of apps and running processes. Look up anything you do not recognize.
• Run an antivirus scan. If you are not sure which to choose, see how to choose an antivirus.
• Check whether your password has leaked. How to do it is in has your password leaked and how to tell.

What to do right away

1. Disconnect the device from the internet so the attacker loses access.
2. From another trusted device change the passwords to important accounts and turn on two-factor authentication.
3. Run an antivirus scan and uninstall unknown apps.
4. If the problem keeps coming back, back up your data and reset the device (reinstall).

How to protect yourself in the future

• Regularly update the system and apps.
• Use an antivirus and strong, unique passwords with two-factor authentication.
• Do not click links and attachments from unknown messages, beware of phishing.
• Install apps only from official stores.

Conclusion

A compromised device usually gives itself away through a combination of signs: sudden slowdowns, overheating, a draining battery, unknown apps and foreign logins. The key is not to panic but to verify it and, if suspicious, quickly change passwords and check the device. If you are not sure, we are happy to check and secure your device.

This article is part of the Cybersecurity overview.