What Is Spyware? Guide to a Secure Defense in 2024

Katarina Glamoslija
Katarina Glamoslija Lead Cybersecurity Editor
Fact-checked by Kate Davidson
Katarina Glamoslija Katarina Glamoslija Lead Cybersecurity Editor
Fact-checked by Kate Davidson

Spyware is a sneaky type of software that steals your personal information without your knowledge. This malicious software can secretly integrate into your system to track your activities, slow down your device, and capture sensitive data like passwords and credit card numbers.

But it doesn’t just look at your sensitive information — it also sends it on to cybercriminals and data brokers. In the most benign cases, victims of spyware will be served targeted ads based on information uncovered. But it can get much worse, with hackers using keyloggers to steal victims’ passwords and personal information or selling their data to real-world criminals.

While spyware can cause serious problems, in most cases, dealing with it is really easy — as long as you follow the steps in this guide carefully. Your very first step should be installing a reputable antivirus app. I like Norton because it scored a 100% malware detection rate in my tests, leaving no stone unturned in the search for spyware.

Threat type Spyware
Devices affected Windows, Mac, Linux, iOS, Android
Sources Malicious downloads or software bundles, phishing links or attachments, compromised websites, malicious ads (malvertising), infected removable drives, physical installation by another person
Symptoms Slow or unresponsive system, high data usage or unusual network connections, unexpected pop-ups or toolbars, changes to homepage or search engine, unexpected redirects in browsers, unauthorized access to accounts, anti-malware alerts detecting spyware
Damage Unauthorized data collection and monitoring, privacy invasion, potential identity theft, targeted advertising, financial loss, exposure to further malware threats through exploited vulnerabilities

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What Is Spyware?

Spyware is an umbrella term for software that monitors and collects information from someone’s device, usually without their knowledge. It can affect PCs, Macs, iPhones, Androids, Linux machines, and virtually any other type of device. While the term spyware has negative connotations, not all spyware is malicious.

For example, some types of spyware have legitimate uses, such as:

  • Monitoring company computers. Companies may use monitoring tools to ensure employees aren’t sharing sensitive information or engaging in unauthorized activities.
  • User-consented tracking. This type of software tracks user behavior to deliver personalized ads and enhance marketing efforts.
  • Parental control software. Parents use this to monitor and manage their children’s online activities, ensuring a safer internet experience.
  • Website cookies. These small files help websites remember your preferences and tailor your browsing experience.

However, when used with malicious intent, spyware can pose a serious threat to your personal security. Criminals often exploit spyware to steal sensitive information and compromise your privacy. Common malicious uses of spyware include:

  • Stealing personal and financial information. Spyware can capture your bank details, intercept personal information like contacts and passwords, and gather enough data to commit identity theft. This can allow attackers to access your accounts, steal your money, and impersonate you for fraudulent purposes.
  • Recording browsing habits for personalized ads. Some spyware tracks your internet browsing to bombard you with targeted ads, often without your consent.
  • Recording messages and calls. This lets attackers snoop on your personal information and use it for malicious purposes.
  • Hijacking your webcam and microphone. Spyware can take control of your webcam and microphone, potentially recording you without your knowledge.

Spotting an Infection

Spyware can be particularly tricky to detect because it often alters your security settings to avoid being discovered. However, there are several red flags that may signal an infection.

Keep an eye out for the following signs:

  • Frequent pop-up ads. If you suddenly start seeing an abundance of pop-up ads while browsing or even when you’re not online, it’s a strong indicator of spyware. Incredibly specific ads can be another sign.
  • Considerably slower device speed. Spyware can consume significant system resources, leading to a noticeable slowdown in your device’s performance.
  • Unsolicited emails or messages. If your contacts report that they are receiving strange emails or messages from you, it could be the work of spyware.
  • Increased freezing or crashing. If your computer begins to freeze or crash more than usual, it could be a sign that spyware is interfering with its normal operations.
  • Drastic increase in CPU usage. Spyware often runs multiple processes in the background, which can cause a significant spike in your device’s CPU usage.
  • Changes to your default browser page. If your browser’s homepage suddenly changes or you’re being redirected to unfamiliar sites, spyware may have hijacked your browser settings.
  • Malfunctioning antivirus or security software. Spyware can disable or interfere with your security software to prevent itself from being detected and removed.
  • Unusual network activity. If you notice unexpected spikes in your data usage or strange network behavior, it might be spyware sending information back to its source.

While each of these factors on its own may not always indicate a severe issue, experiencing several at the same time is a strong sign that your device might be infected with spyware.

How Can Your Device Get Infected with Spyware?

Spyware can infiltrate your device through various channels. Here are the most common ways:

  • Phishing emails. Cybercriminals often send emails that appear legitimate but contain malicious links or attachments. Clicking on these links or opening the attachments can download spyware onto your device, compromising your security.
  • Malicious websites. These sites may look genuine, but they’re designed to automatically download spyware onto your device when you visit or interact with them. Even simple actions like clicking on a pop-up ad or banner can trigger the download.
  • Software downloads. Downloading software from untrusted or unofficial sources can put you at risk of a spyware infection. Spyware is often bundled with otherwise legitimate programs. These downloads might offer attractive features but secretly install malicious software along with the desired application.
  • Fake software updates. Pop-up notifications that mimic official update alerts can lead you to download spyware if you follow their instructions. These fake updates often exploit vulnerabilities in outdated software to gain access to your system.
  • Infected USB drives. Using USB drives that have been compromised or used in another infected system can transfer spyware to your device when plugged in. Simply inserting an infected USB drive can initiate the transfer of malicious files to your computer.
  • Instant messaging and social media. Links shared through chat apps or social media platforms can lead to sites that silently install spyware on your device. Even trusted contacts can unknowingly forward compromised links that seem harmless at first glance.
  • Mobile apps. Downloading apps from unofficial app stores or directly from the web can install spyware, as these sources may lack stringent security checks. Even apps on official app stores can request excessive permissions or contain hidden code that captures your personal data.

By understanding these infection methods, you can take precautions to protect your devices from spyware and maintain your privacy.

Most Common Types of Spyware

Like other types of malware, spyware can spread by a variety of means, from email attachments to sketchy downloads. Generally, spyware is categorized based on what it does rather than how it spreads. Here are some of the most common categories:

Adware

This is the most common form of spyware and one of the most common threats to both businesses and consumers.

Adware floods the user with popup ads. In some cases, this will occur even when the victim does not have a browser open. And while this might be seen as more of a nuisance than anything, adware can also enable attackers to spy on your browser history and sell data on the dark web. In addition to a greater quantity of ads, highly specific ads are another sign of adware.

Keyloggers

Keyloggers are one of the most subtle and dangerous forms of spyware. They allow attackers to monitor and record everything you type on your keyboard.

Think of all the different inputs this would apply to — search history, passwords, messaging, email activity, credit card info, and more. All of that information can give attackers more than enough data to either sell for a profit or use as a stepping stone to commit identity theft.

Complete Surveillance Tools

These tools are sophisticated pieces of spyware often developed by elite hackers or government agencies. They can monitor every aspect of a target’s digital life, from keystrokes to location tracking. They frequently use zero-click exploits, which allow them to infiltrate devices without any user interaction.

One notorious example is Pegasus, a spyware capable of accessing messages, camera feeds, and more, all without leaving a trace. These tools represent the pinnacle of spyware technology, making them exceptionally dangerous and difficult to detect or remove.

Mobile Spyware

Mobile spyware often infiltrates devices through malicious apps or by exploiting vulnerabilities in mobile messaging. Downloading apps from unverified or untrustworthy sources significantly increases the risk of spyware infection. Additionally, unencrypted messages, like those sent via SMS or MMS, are particularly vulnerable to interception.

Some mobile apps will be nothing but spyware, tracking you in various ways while offering you nothing in return. Others may provide some benefit but will snoop on you in the process. Review an app’s permission before you install it. Some tools, like Norton’s App Advisor, make this easy by providing a list of apps and outlining which ones have excessive permissions.

How to Prevent Spyware

Spyware can get onto your devices in sneaky ways — so here are some important tips you should follow to prevent it in the first place:

  • Use reliable antivirus software: A comprehensive internet security suite can stop spyware before it gets installed on your computer. Choose a good antivirus program that offers real-time monitoring, specific detection and removal options for spyware, and ensure it’s regularly updated to combat the latest spyware threats.
  • Never click on ads: A significant percentage of online ads contain spyware. Avoid clicking on any ads to reduce the risk of infection. If you see something you’re interested in buying, search for the item or brand instead and purchase it directly from the official site or another reputable website.
  • Read reviews before downloading software: Research any apps carefully before you download them, and whenever possible only download from the official website. Most trusted products will come with reviews, so always check these first to ensure you’re dealing with a reputable product.
  • Adjust your browser security settings: Browsers offer a range of security settings that allow you to control how your data is used. You can choose to block cookies completely, allow them for specific sites, or set preferences to share only certain information. Regularly monitor your security settings to stay aware of any changes.
  • Engage in smart browsing: Never open an email attachment or message from someone you don’t know, and never visit websites that don’t have “https://” before the rest of the domain name. If you receive a suspicious link from a friend, confirm that it is actually from them before clicking. Pop-ups claiming you’ve won a prize, like money or an iPhone, should never be trusted.
  • Avoid accidentally clicking on pop-ups when closing them: Many infected ads make themselves difficult to close by using deceptive design elements like a fake X button. Be vigilant when closing pop-ups to avoid accidentally opening the link. Instead, use Alt + F4 on Windows or Command + W on macOS, or carefully click the correct X button in the corner of the pop-up.
  • Use a firewall: Firewalls filter your network and provide a strong defense against risky websites. The best firewalls make it difficult for spyware to enter your computer and prevent them from exfiltrating your data. Typically, firewalls come as part of a good antivirus package, which often includes other powerful internet security features like a VPN. Look for antiviruses that include firewall protection.
  • Educate your family about the risks: If you have young children, it’s crucial they understand the risks of spyware. Homes with children under 18 are more likely to have computers infected with spyware. Teach young people how to recognize and avoid suspicious links and downloads to help them stay safe online.

How to Remove Spyware

If you suspect that your devices have been infected with spyware, the first step is to turn off your internet connection. The infection works by sending your data back via the web, so this puts an immediate stop to the process. Once you’ve done this, you have 2 options:

Remove Spyware Using Software

  • Run a full system scan with antivirus software.  A good antivirus will detect 100% of malware. I highly recommend using Norton to perform a full system scan, because it detected 100% of malware in my tests.
  • Quarantine and delete any malware. Once Norton (or your antivirus of choice) has quarantined any malware, it’s generally safe to go ahead and delete it. Good modern antiviruses are really adept at knowing what’s malware and what’s safe.
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Remove Spyware Manually

If you know the source of the problem, you can remove it by hand. Open up your application menu to view all of the active programs. Identify the app that is causing the problem, right-click, and uninstall it (the exact process will vary depending on which operating system you use).

Be aware that manual removal does come with its risks. If you choose the wrong program, you could lose vital data or even make your computer inoperable. Always select the option to hide system programs and do a search for the name online before deleting anything completely.

Prevent Spyware & Protect Your Data

As we’ve mentioned above, the very best protection against spyware is not letting it get onto your device in the first place. But quite often, it’s already too late for prevention and you need to focus instead on removing the threat from your computer either manually or by using an antivirus.

Either way, now that you’re aware of the threats of spyware, the solution is the same: follow these steps to prevent an infection in the future and, if you are infected, remove it quickly and efficiently using a good security solution.

Frequently Asked Questions

What is spyware?

Spyware is software that’s designed to track users. Depending on the type, it can track which websites you visit, gather general information about how you use your device, or even log every single word you type (these are called keyloggers).

Nowadays tracking is quite prevalent, with most applications collecting a variety of data about every user.  But the term spyware is generally reserved for programs whose main purpose is to spy on the user without providing them with any benefits. Most spyware is legal, but there are many exceptions.

What data can spyware collect?

Spyware comes in several forms that engage in different types of data collection. They can collect a wide range of data, including keystrokes, browsing history, login credentials, personal messages, financial information, and even audio or video recordings from device microphones or cameras. Spyware is everywhere, but there are steps you can take to avoid it.

Is spyware illegal?

It can be, but a lot of it is perfectly legal. In most cases, it’s illegal to distribute spyware without the consent of the person being monitored. But tons of spyware takes the form of user-consented tracking, which is generally legal. Having your data collected is pretty much unavoidable these days, but there are steps you can take to avoid the worst offenders. Even if it’s legal, you definitely want to avoid spyware.

Can I get spyware on my phone?

Absolutely. Mobile spyware might just be the most common type of spyware. Every app you download will demand certain permissions. These can be highly intrusive, with the app tracking your location, the words you type, and more. If an app asks for these while providing you with virtually no benefit, it’s spyware. Always review the permissions when you install a new app and consider whether you accept the potential that you’ll be tracked. Luckily, spyware mobile apps can be removed.

What should I do if I suspect my device has spyware?

To start, I recommend running an antivirus scan. A good antivirus will detect PUPs and other programs that collect excessive data about the user. Some programs can be removed manually, but if you’re dealing with something truly malicious like a keylogger, you probably need specialized software to deal with the threat.

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About the Author
Katarina Glamoslija
Katarina Glamoslija
Lead Cybersecurity Editor

About the Author

Katarina Glamoslija is Lead Cybersecurity Editor at SafetyDetectives. She has more than a decade of experience researching, testing, and reviewing cybersecurity products and investigating best practices for online safety and data protection. Before joining SafetyDetectives, she led several tech websites, including one about antiviruses and another about VPNs. She also worked as a freelance writer and editor for tech, medical, and business publications. When she’s not a “Safety Detective”, she can be found traveling (and writing about it on her small travel blog), playing with her cats, and binge-watching crime dramas.

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