Cyberattack Definition
A cyberattack is a deliberate attempt by an individual or group to gain unauthorized access to a computer system, network, or device in order to steal, expose, alter, disable, or destroy data. Attacks are carried out for financial gain, espionage, disruption, or ideological motives, and they target organizations of every size as well as individuals.
Cyberattacks range from opportunistic and automated — like phishing campaigns blasted to thousands of inboxes — to highly targeted, long-running intrusions by organized criminal groups or nation-state actors. Common forms include ransomware, phishing, malware, denial-of-service attacks, and credential-based intrusions where attackers simply log in using stolen passwords.
What are the most common types of cyberattacks?
The most common cyberattacks fall into a handful of recognizable categories. Phishing uses fraudulent emails or messages to trick victims into revealing credentials or opening malicious files. Ransomware encrypts an organization's data and demands payment for its release, often after exfiltrating the data first. Malware covers the broader family of malicious software, including infostealers, trojans, and spyware. Denial-of-service (DoS/DDoS) attacks flood systems with traffic to knock them offline. Credential-based attacks, including credential stuffing and account takeover, use stolen logins to access systems without exploiting any technical flaw. Others include man-in-the-middle interception, SQL injection against web applications, and supply chain attacks that compromise a trusted vendor to reach their customers.
How do cyberattacks happen?
Most cyberattacks follow a recognizable progression. Attackers begin with reconnaissance, researching a target's employees, exposed systems, and vendors. They then find an initial access point — most often a phishing email, stolen credentials, an unpatched vulnerability, or a compromised third party. Once inside, they establish persistence by installing a backdoor and connecting to command-and-control infrastructure, so they retain access even if the original entry is closed. From there they move laterally, escalating privileges and identifying valuable data. Finally, they act on objectives: exfiltrating data, deploying ransomware, or committing fraud. Critically, attackers increasingly don't break in at all — they log in with valid credentials bought from the criminal underground.
How can organizations prevent cyberattacks?
No single control prevents every attack, so effective defense is layered — and increasingly, organizations consolidate those layers with integrated platforms like the ones Fortra offers. Multi-factor authentication, ideally phishing-resistant methods like passkeys, blocks the credential-based attacks that drive most breaches. Email security filters the phishing messages behind the majority of initial compromises, while data loss prevention (DLP) and data classification ensure sensitive information is identified and protected before it can be exfiltrated. Vulnerability management and offensive security testing close the known flaws attackers automate against, and managed detection and response provides the continuous monitoring needed to catch command-and-control activity and lateral movement before data leaves the network. Rounding out the stack, security awareness training reduces the human error attackers rely on, tested backups limit ransomware leverage, and a rehearsed incident response plan ultimately determines how much damage an attack causes.