17 Types of Cyber Attacks Commonly Used By Hackers

What Is a Cyber Attack? How Do They Happen?

A cyber attack is an unlawful attempt to obtain access to a computer or computer system to cause intentional damage. Cybercrime, cyber warfare, or cyberterrorism can result in debilitating data breaches or financial losses for both companies and individuals.

According to the latest data from the FBI's Internet Crime Complaint Center (IC3) [*]:

Americans lost over $10.2 billion to cybercrime last year — nearly a 35% increase from the year before.

Cyber attacks can target anyone or anything connected to the internet. Individual users, large organizations, essential public services, governments, or even whole countries.

In this guide, we'll cover the most common types of cyber attacks, and what you can do to protect yourself, your family, or your business from hackers and online criminals.

The 17 Most Common Types of Cyber Attacks

1. Malware-based attacks
2. Phishing attacks
3. Man-in-the-middle attacks
4. Denial of Service attacks
5. SQL injection attacks
6. DNS tunneling
7. Zero-day exploits
8. Password attacks
9. Drive-by download attacks
10. Cross-site scripting (XSS) attacks
11. Rootkits
12. DNS spoofing
13. Internet of Things (IoT) attacks
14. Session hijacking
15. URL manipulation
16. Cryptojacking
17. Inside threats‍

1. Malware-based attacks (Ransomware, Trojans, etc.)

Malware refers to “malicious software” that is designed to disrupt or steal data from a computer network or server.

Hackers trick you into installing malware on your devices. Once installed, a malicious script runs in the background and bypasses your security —  giving hackers access to your sensitive data, and the opportunity to even hijack control. 

Malware is one of the most commonly used cyber attacks. You should be aware of these variations.

• Ransomware: This type of malware encrypts files on your system and blocks access until you pay a “ransom” (usually in cryptocurrency). Extortion-only attacks are similar to ransomware in that they demand payments for stolen confidential information. Such data heists, however, don’t involve data-scrambling malware or decryption keys.
• Spyware: As the name suggests, this type of malware spies on your activities and sends data back to the hacker. This could include bank details, logins, and passwords.
• Keyloggers: Keyloggers are similar to spyware, except that they track your activities. Everything you type (and the site you type it in) is sent to the hacker and can be used for blackmail or identity theft.
• Trojans: Named after the famous Trojan horse, these types of malware “hide” inside a legitimate piece of software. For example, you might download what you think is antivirus software — only to have your device infected. 
• Viruses: Viruses attach to programs and files and are triggered when you open them. Once active, a virus can self-replicate without your knowledge and slow down your device or destroy data. There are also "worms", which are viruses that move throughout your network from one infected computer to the next, giving hackers remote access to your entire system.

Malware attacks can happen to individuals — like when you open a link in a phishing email. But they’re also used to attack businesses and organizations.

In May 2021, JBS USA, the world’s largest meat supplier, was hit with a ransomware attack that shut down production at many of its plants. The company ended up paying a ransom of $11 million in Bitcoin to prevent further damage [*].

2. Phishing attacks (spear phishing, whaling, etc.)

A phishing attack occurs when a cybercriminal sends you a fraudulent email, text (called “smishing”), or phone call (called “vishing”). These messages look like they’re from someone official or a person or business who you trust – such as your bank, the FBI, or a company like Microsoft, Apple, or Netflix. 

In actuality, these messages are sent from imposters. If you reply with sensitive information such as your password, they can use it to take over your accounts. 

Phishing and smishing messages may also instruct you to click on a link or open an email attachment that will either download malware to your device or send you to a phishing site designed to steal your information. 

In many cases, phishing attacks cast a wide net and don’t target specific individuals (this makes them easier to identify). However, there are a few new phishing cyber attacks that are more targeted and harder to spot. These include:

• Spear phishing attacks: These attacks are usually sent via email and target a specific individual. The hacker will use your personal information that they have bought on the Dark Web (or found in your online footprint and on social media) to make it sound more believable and get you to click on the link. 
• Whaling: A whale phishing attack occurs when a hacker targets high-profile individuals, like CEOs and executives. The goal is to steal their credentials and get backdoor access to their company’s network. CEO fraud is now a $26-billion-a-year scam [*].
• Angler phishing attacks: An Angler attack is a new type of phishing scam in which a hacker “baits” users on social media by pretending to be a well-known company’s customer service account. Scammers create accounts like “@AmazonHelp$” and then auto-respond to relevant messages by providing a link for you to talk to a “rep.” But really, it’s a scam designed to steal your information.

Scammers are getting more sophisticated with phishing attacks which makes it harder to identify when you’re a target. 

A good rule of thumb is to always question unsolicited messages — especially from anyone claiming to be from a government agency or large corporation. If they call or message you, contact the company directly by obtaining contact information from their website instead of engaging with the message.

📚 Related: The 11 Latest Telegram Scams To Watch Out For →

3. Man-in-the-middle attacks

A man-in-the-middle attack (MitM) occurs when attackers intercept data or compromise your network to “eavesdrop” on you. These attacks are especially common when using public Wi-Fi networks, which can easily be hacked. 

For example, let’s say you’re using the Wi-Fi at Starbucks and need to check your bank account balance. When you log in, a hacker can intercept your data and capture your username and password (and drain your account later). 

MitM attacks can also be used to “spoof” conversations. Hackers insert themselves into your conversation and pretend to be the person you think you’re talking to. 

In one extreme example, a hacker intercepted communications between a Chinese investor and a startup founder and got them to change the destination of a $1 million wire transfer [*].

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4. Denial of Service (DOS) and Distributed Denial of Service (DDoS)

Many cyber attacks are meant to overwhelm servers, forcing services to shut down. 

A denial of service (DOS) attack occurs when hackers use false requests and traffic to overwhelm a system and shut it down. A distributed denial of service (DDoS) attack is the same type of attack, except the hacker uses multiple breached devices at the same time. 

The goal of these cyber attacks isn’t usually to steal data, but to halt or even shut down business operations. DDoS attacks have shut down sites like Twitter, SoundCloud, and Spotify, and even severely damaged Amazon’s AWS [*].

5. SQL injection attacks

Most websites use SQL databases to store sensitive information like logins, passwords, and account information. Hackers use an SQL injection attack to “trick” the database into giving up this information. 

These attacks are a bit technical, but they come down to a hacker entering predefined SQL commands into a data-entry box (like a login or password field). Those commands can read sensitive data, modify database data, or even trigger executive functions (such as shutting down the system).  

Just last year, 70 gigabytes of data was stolen from Gab — a far-right website — through an SQL injection attack [*].

📚 Related: Does a VPN Protect You From Viruses? →

6. DNS tunneling

DNS tunneling is a type of cyber attack that hackers use to bypass traditional security systems like firewalls to gain access to systems and networks. Hackers encode malicious programs within DNS queries and responses (that most security programs ignore). 

Once the program is inside, it latches onto the target server, giving the hackers remote access. 

DNS tunneling attacks are especially dangerous as they often go unnoticed for days, weeks, or months. During that time, cybercriminals can steal sensitive data, change code, install new access points, and even install malware. 

In one example, cybercriminals used DNS tunneling to attack Air India and other airlines and steal passport details and credit card numbers. The “backdoor” was open for more than two months [*]. 

7. Zero-day exploits and attacks

Zero-day exploits are cybersecurity vulnerabilities that exist in a software or network without the manufacturer’s knowledge. For example, Apple might release a new version of iOS that accidentally contains a way for hackers to steal your iCloud information. Once they discover the flaw, the attacked company has “zero days” to fix it, as they’re already vulnerable. 

A zero-day attack occurs when hackers use those vulnerabilities to get into a system to steal data or cause damage. In the first few months of 2022, Microsoft, Google, and Apple all had to patch zero-day bugs [*]. 

One of the most dangerous zero-day vulnerabilities was discovered late last year when researchers found a vulnerability in “Log4J” — a Java-based utility that is used in everything from Apple’s iCloud to the Mars Rover.

8. Password attacks

Password attacks comprise any cyber attacks in which hackers try to guess, brute force, or trick you into giving up your passwords. 

There are a few different password-based cyber attacks you need to be aware of: 

• Password spraying: This is when hackers attempt to use the same password across many accounts. For example, over 3.5 million Americans use the password “123456”.
• Brute force: A brute force attack occurs when hackers create software that tries different combinations of usernames and passwords until finding one that works. They’ll often use logins leaked to the Dark Web because many people reuse passwords across accounts (this is also called the “Dictionary” method).
• Social engineering: Social engineering attacks occur when hackers use psychology to trick you into giving up your password. For example, they might use a phishing email pretending to be from your bank and fool you into “confirming” your account details. 

📚 Related: What Is Credential Stuffing (and How To Protect Yourself) →

9. Drive-by download attacks

Most cyber attacks require some action from you — like clicking on a link or downloading an attachment. But a drive-by attack (or drive-by download) occurs when you just browse an infected website. 

Hackers take advantage of vulnerabilities in plug-ins, web browsers, and apps to install malware on your device without your knowledge.  

Back in 2016, a drive-by download attack used vulnerabilities in Adobe Flash Player to install crypto-ransomware [*]. Once installed, victims were redirected to a site demanding 0.05 bitcoin to return access to their device.

10. Cross-site scripting attacks

A cross-site scripting (XSS) attack allows hackers to gain unauthorized access to an application or website. 

Cybercriminals take advantage of vulnerable websites and cause them to install malicious JavaScript to users. When the code executes in your browser, the hacker is able to masquerade as your account and do anything you can do. 

Sites vulnerable to XSS include message boards, forums, and web pages. These pages depend on user input that is not screened for malicious codes. But even larger sites are at risk. 

For example, in 2014, a site vulnerability on eBay led to customers being redirected to malicious sites upon clicking on product links [*]. The sites displayed fake eBay login pages, prompting users to enter their details which were then stolen.

11. Rootkits

Rootkits are a type of malware that give hackers control and administrator-level access to the target system. Rootkits hide deep inside your device’s operating system, making them hard to detect but also incredibly dangerous. 

A rootkit could allow hackers to steal sensitive information, install keyloggers, or even remove antivirus software. For example, in July 2022, Kaspersky uncovered a rootkit that can persist on a victim's machine even after a reboot or reinstallation [*].

📚 Related: What To Do if Your SSN Is on the Dark Web →

12. DNS spoofing or “poisoning”

Domain Name System (DNS) spoofing allows hackers to send online traffic to a “spoofed” website. These sites look nearly identical to your destination (for example, the login page for your bank or a social media account). But any information you submit goes straight to the hackers, giving them access to your accounts. 

Hackers can also use DNS spoofing to sabotage companies by redirecting their site visitors to a poor-quality site with obscene content. 

In one famous example, Google’s homepage was spoofed in Romania and Pakistan [*], sending users to an unfamiliar site. Thankfully, in this case, the hacker did not seem to have malicious intent other than redirecting visitors. 

13. Internet of Things (IoT) attacks

Internet of Things (IoT) devices, such as your smart speakers, TVs, and toys can also be the targets of cyber attacks. An IoT attack occurs when hackers steal data from a device — or string together multiple IoT devices into a botnet — that can be used for DDoS attacks. 

IoT devices usually don’t have antivirus software installed, making them easy targets for hackers. Many of the world’s largest DDoS attacks used “bot armies” composed of IoT devices. It may seem unlikely, but even your “smart fridge” could be an unwitting soldier in a cyber attack.  

📚 Related: The Worst Instagram Scams Happening Right Now →

14. Session hijacking

Session hijacking is a type of man-in-the-middle attack in which the attacker “takes over” a session between a client and the server. The attacker’s computer swaps its IP address for the client’s address and continues to access the server, without needing any sort of authentication. 

Once they’ve hijacked a session, hackers can do anything the client’s account could do. For example, let’s say you’re accessing your company’s internal database while on a work trip. If a hacker hijacks your session, they’ll gain access to all of your company files.

15. URL manipulation

URL manipulation occurs when hackers alter the parameters in a URL address to redirect you to a phishing site or download malware. 

For example, many people use URL shorteners to help remember long web addresses or specific pages. If hackers “poison” that shortened URL, they can send you to a phishing site designed to steal your personal information. 

In other situations, hackers manipulate the URL to get the server to show pages they shouldn’t have access to. For example, they might enter “www.yoursitename.com/admin” to find your login page or enter “www.yoursitename.com/.bak” to get access to backup files. 

📚 Related: How To Detect and Remove Malware From Your Computer →

16. Cryptojacking

Cryptojacking is a cyber attack that secretly uses your computer’s processing power to mine for cryptocurrencies like bitcoin and Ethereum. This will severely slow down your computer systems and cause other potential vulnerabilities. 

While not necessarily an “attack,” Norton is facing harsh criticism after revelations that their latest update quietly installed a cryptominer inside its antivirus software. 

17. Inside threats

Cyber attacks often come from an external threat like a hacking group. But there’s also the possibility of insider threats. Inside threats occur when someone who works for a company purposefully steals data, gives someone unauthorized access, or leaks passwords.  

For example, at the start of the COVID-19 pandemic, a disgruntled former staff member of a medical device packaging company used his administrator access to wipe over 100,000 company records [*].

📚 Related: The 15 Types of Hackers You Need To Be Aware Of →

Hackers Are Getting Smarter — Aura Helps You Stay Safe

Cyber attacks aren’t slowing down anytime soon. But that doesn’t mean you can’t protect yourself from criminals who want to access your data or compromise your devices. 

Learn how to recognize imminent cybersecurity threats and how criminals can commandeer your devices. And for added protection, consider signing up for Aura. 

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