What is a cyberattack? A guide to the different methods cybercriminals use to harm computers and steal data

What is a cyberattack? A guide to the different methods cybercriminals use to harm computers and steal data
Cyberattacks are performed by malicious actors with various intentions, though the tools and methods they use are often the same.Bill Hinton/Getty Images
  • A cyberattack is an assault on any computer or network, almost always launched from another computer or network.
  • There are a lot of ways malicious actors can launch a cyberattack, including malware, zero-day exploits, and denial-of-service attacks.
  • Here's a brief overview of cyberattacks and what you need to know about their risk.

We live in an age in which every major government, military organization, corporation, and medical institution relies on computer technology for nearly every aspect of its operation, and those systems are always at risk of being attacked.

A cyberattack is just that: an assault on a computer, computer network, or the data stored within that network. The intent of the attack can vary - some attacks are intended to disable the computer system while others intend to gain control over it. Still others intend to infiltrate the system to steal or destroy data. While cyberattacks are often aimed at organizations, individuals are not immune from cyberattack either.

It's important to understand that cyberattacks can be launched by any kind of malicious actor, including criminals whose primary goal is monetary gain, state actors trying to gain leverage through intelligence gathering, corporate espionage or other spycraft, and terrorists attempting to damage, destroy, or gain access to computer systems. The tools and methods used by all these malicious actors may be largely the same.

Types of cyberattacks

There are a number of common kinds of cyberattacks. They include:

  • Malware: This is a general term that describes all manner of malicious software including viruses, Trojans, worms, and more. Depending on the software, it might be able to steal data, block access to the PC, remotely control it, and more.
  • Ransomware: Sometimes considered a kind of malware, ransomware is worth also discussing on its own because of how serious the risk has become. A ransomware infection can encrypt a computer and hold the data for ransom; its frequency has ballooned in recent years.
  • Zero-day exploits: This refers to any attack that leverages a known security flaw in a computer system after the problem is discovered but before a security patch can be deployed to fix it.
  • Phishing: In a phishing attack, a malicious email or text message can impersonate a legitimate message, luring users to accidentally give up sensitive information or login credentials for computer systems.
  • Man-in-the-middle (MITM): This is an attack in which a malicious user manages to take control of a node between a user and a destination on the network or internet. For example, a MITM attack might use a compromised Wi-Fi hotspot to masquerade as a site that users need to log into, allowing the MITM to harvest critical information.
  • Denial-of-service (DoS): In a denial of service attack, a malicious user overwhelms a computer system with traffic or data requests so it can't perform any legitimate activities. This is often in the form of a distributed denial-of-service (DDoS) attack, in which a large number of computers are used for the attack, often remotely controlled by malware without the actual owner's knowledge.
  • SQL injection: Many computer networks rely on Structured Query Language (SQL) databases for internal storage and operation. An SQL injection attack occurs when an attacker inserts SQL commands to the computer (such as via a form on a webpage). If the network's security isn't robust enough, it might allow that SQL instruction to be processed, which can compromise the network.

How to prevent a cyberattack

There is an entire industry focused on preventing cyberattacks, staffed with IT and cybersecurity professionals.


To prevent attacks, teams of cybersecurity personnel typically develop detailed protection plans that include operational security procedures designed to protect physical systems and the data stored within those networks. This includes data access procedures, identity and credential verification, user training and education, and more.

IT professionals also install and manage anti-malware software and train users to recognize and deal with spam, phishing attacks, and malware that slips through the filters and protective software. Organizations also invest in firewalls along with other security tools and processes.

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