Home Topics What is a cyberattack? What is a cyberattack?
Explore IBM's cyberattack solution Subscribe to Security Topic Updates
Illustration with collage of pictograms of clouds, mobile phone, fingerprint and check mark
What is a cyberattack?

A cyberattack is any intentional effort to steal, expose, alter, disable, or destroy data, applications, or other assets through unauthorized access to a network, computer system or digital device.

Threat actors start cyberattacks for all sorts of reasons, from petty theft to acts of war. They use various tactics, like malware attackssocial engineering scams, and password theft, to gain unauthorized access to their target systems.

Cyberattacks can disrupt, damage and even destroy businesses. The average cost of a data breach is USD 4.35 million. This price tag includes the costs of discovering and responding to the violation, downtime and lost revenue, and the long-term reputational damage to a business and its brand.

But some cyberattacks can be considerably more costly than others. Ransomware attacks have commanded ransom payments as high as USD 40 million (link resides outside ibm.com). Business email compromise (BEC) scams have stolen as much as USD 47 million from victims in a single attack (link resides outside ibm.com). Cyberattacks that compromise customers' personally identifiable information (PII) can lead to a loss of customer trust, regulatory fines, and even legal action. By one estimate, cybercrime will cost the world economy USD 10.5 trillion per year by 2025 (link resides outside ibm.com). 

Cost of a Data Breach

Get insights to better manage the risk of a data breach with the latest Cost of a Data Breach report.

Related content

Register for the X-Force Threat Intelligence Index

Why do cyberattacks happen? 

The motivations behind cyberattacks can vary, but there are three main categories: 

  1. Criminal
  2. Political 
  3. Personal

Criminally motivated attackers seek financial gain through monetary theft, data theft, or business disruption. Cybercriminals may hack into a bank account to steal money directly or use social engineering scams to trick people into sending money to them. Hackers may steal data and use it to commit identity theft or sell it on the dark web or hold it for ransom.

Extortion is another tactic that is used. Hackers may use ransomware, DDoS attacks, or other tactics to hold data or devices hostage until a company pays. However, according to the most recent X-Force Threat Intelligence Index, 32 percent of cyber incidents involved the theft and sale of data rather than encryption for extortion.

Personally motivated attackers, such as disgruntled current or former employees, primarily seek retribution for some perceived slight. They may take money, steal sensitive data, or disrupt a company's systems.

Politically motivated attackers are often associated with cyberwarfare, cyberterrorism, or "hacktivism." In cyberwarfare, nation-state actors often target their enemies' government agencies or critical infrastructure. For example, since the start of the Russia-Ukraine War, both countries have experienced a rash of cyberattacks against vital institutions (link resides outside ibm.com). Activist hackers, called "hacktivists," may not cause extensive damage to their targets. Instead, they typically seek attention for their causes by making their attacks known to the public.

Less common cyberattack motivations include corporate espionage, in which hackers steal intellectual property to gain an unfair advantage over competitors, and vigilante hackers who use a system’s vulnerabilities to warn others about them. Some hackers hack for sport, savoring the intellectual challenge.

Who is behind cyberattacks?

Criminal organizations, state actors, and private persons can all start cyberattacks. One way to classify threat actors is by categorizing them as outsider threats or insider threats.

Outsider threats aren’t authorized to use a network or device but break in anyway. External cyberthreat actors include organized criminal groups, professional hackers, state-sponsored actors, amateur hackers, and hacktivists.

Insider threats are users who have authorized and legitimate access to a company’s assets and misuse their privileges deliberately or accidentally. This category includes employees, business partners, clients, contractors, and suppliers with system access.

While negligent users can put their companies at risk, it’s only a cyberattack if the user intentionally uses their privileges to carry out malicious activity. An employee who carelessly stores sensitive information in an unsecured drive isn’t committing a cyberattack — but a disgruntled employee who knowingly makes copies of confidential data for personal gain is. 

What do cyberattacks target?

Threat actors typically break into computer networks because they’re after something specific. Common targets include:

  • Money
  • Businesses' financial data
  • Client lists
  • Customer data, including personally identifiable information (PII) or other sensitive personal data
  • Email addresses and login credentials
  • Intellectual property, like trade secrets or product designs

In some cases, cyberattackers don’t want to steal anything at all. Rather, they merely want to disrupt information systems or IT infrastructure to damage a business, government agency, or other target. 

What effects do cyberattacks have on businesses? 

If successful, cyberattacks can damage enterprises. They can cause downtime, data loss, and money loss. For example:

  • Hackers can use malware or denial-of-service attacks to cause system or server crashes. This downtime can lead to major service interruptions and financial losses. According to the Cost of a Data Breach report, the average breach results in USD 1.42 million in lost business.

  • SQL injection attacks allow hackers to alter, delete, or steal data from a system.

  • Phishing attacks allow hackers to trick people into sending money or sensitive information to them.

  • Ransomware attacks can disable a system until the company pays the attacker a ransom. According to one report (link resides outside ibm.com), the average ransom payment is USD 812,360.

In addition to directly harming the target, cyberattacks can have a host of secondary costs and consequences. For example, the Cost of a Data Breach report found that businesses spend an average of USD 2.62 million on detecting, responding to, and remediating breaches.

Cyberattacks can also have repercussions for victims beyond the immediate target. In 2021, the DarkSide ransomware gang attacked the Colonial Pipeline, the largest refined oil pipeline system in the US. The attackers entered the company’s network by using a compromised password (link resides outside ibm.com). They shut down the pipeline that carries 45% of the gas, diesel, and jet fuel supplied to the US East Coast, leading to widespread fuel shortages.

The cybercriminals demanded a ransom of almost USD 5 million in bitcoin cryptocurrency, which Colonial Pipeline paid (link resides outside ibm.com). However, with help from the US government, the company eventually recovered USD 2.3 million of the ransom.

What are the common types of cyberattacks?

Cybercriminals use many sophisticated tools and techniques to start cyberattacks against enterprise IT systems, personal computers, and other targets. Some of the most common types of cyberattacks include:


Malware is malicious software that can render infected systems inoperable. Malware can destroy data, steal information, or even wipe files critical to the operating system’s ability to run. Malware comes in many forms, including:

  • Trojan horses disguise themselves as useful programs or hide within legitimate software to trick users into installing them. A remote access Trojan (RAT) creates a secret back door on the victim’s device, while a dropper Trojan installs additional malware once it has a foothold.

  • Ransomware is sophisticated malware that uses strong encryption to hold data or systems hostage. Cybercriminals then demand payment in exchange for releasing the system and restoring functionality. According to IBM’s X-Force Threat Intelligence Index, ransomware is the second most common type of cyberattack, accounting for 17% of attacks.

  • Scareware uses fake messages to frighten victims into downloading malware or passing sensitive information to a fraudster.

  • Spyware is a type of malware that secretly gathers sensitive information, like usernames, passwords, and credit card numbers. It then sends this information back to the hacker.

  • Rootkits are malware packages that allow hackers to gain administrator-level access to a computer’s operating system or other assets.

  • Worms are self-replicating malicious code that can automatically spread between apps and devices. 
Social engineering

Social engineering attacks manipulate people into doing things that they shouldn’t do, like sharing information they shouldn’t share, downloading software they shouldn’t download, or sending money to criminals.

Phishing is one of the most pervasive social engineering attacks. According to the Cost of a Data Breach report, it is the second most common cause of breaches. The most basic phishing scams use fake emails or text messages to steal users’ credentials, exfiltrate sensitive data, or spread malware. Phishing messages are often designed to look as though they’re coming from a legitimate source. They usually direct the victim to click a hyperlink that takes them to a malicious website or open an email attachment that turns out to be malware.

Cybercriminals have also developed more sophisticated methods of phishing. Spear phishing is a highly targeted attack that aims to manipulate a specific individual, often by using details from the victim’s public social media profiles to make the ruse more convincing. Whale phishing is a type of spear phishing that specifically targets high-level corporate officers. In a business email compromise (BEC) scam, cybercriminals pose as executives, vendors, or other business associates to trick victims into wiring money or sharing sensitive data. 

Denial-of-service attacks

Denial-of-service (DoS) and distributed denial-of-service (DDoS) attacks flood a system's resources with fraudulent traffic. This traffic overwhelms the system, preventing responses to legitimate requests and reducing the system's ability to perform. A denial-of-service attack may be an end in itself or a setup for another attack.

The difference between DoS attacks and DDoS attacks is simply that DoS attacks use a single source to generate fraudulent traffic, while DDoS attacks use multiple sources. DDoS attacks are often carried out with a botnet, a network of internet-connected, malware-infected devices under a hacker's control. Botnets can include laptops, smartphones, and Internet of Things (IoT) devices. Victims often don't know when a botnet has hijacked their devices.

Account compromise

Account compromise is any attack in which hackers hijack a legitimate user's account for malicious activity. Cybercriminals can break into a user's account in many ways. They can steal credentials through phishing attacks or buy stolen password databases off the dark web. They can use password attack tools like Hashcat and John the Ripper to break password encryptions or stage brute force attacks, in which they run automated scripts or bots to generate and test potential passwords until one works.

Man-in-the-middle attacks

In a man-in-the-middle (MiTM) attack, also called an "eavesdropping attack," a hacker secretly intercepts communications between two people or between a user and a server. MitM attacks are commonly carried out via unsecured public wifi networks, where it's relatively easy for threat actors to spy on traffic.

Hackers may read a user's emails or even secretly alter the emails before they reach the recipient. In a session hijacking attack, the hacker interrupts the connection between a user and a server hosting important assets, like a confidential company database. The hacker swaps their IP address with the user's, making the server think they're a legitimate user logged into a legitimate session. This gives the hacker free rein to steal data or otherwise wreak havoc. 

Supply chain attacks

Supply chain attacks are cyberattacks in which hackers breach a company by targeting its software vendors, material suppliers, and other service providers. Because vendors are often connected to their customers' networks in some way, hackers can use the vendor's network as an attack vector to access multiple targets at once.

For example, in 2020, Russian state actors hacked the software vendor SolarWinds and distributed malware to its customers under the guise of a software update (link resides outside ibm.com). The malware allowed Russian spies to access the sensitive data of various US government agencies using SolarWinds' services, including the Treasury, Justice, and State Departments. 

Other types of cyberattacks
Cross-site scripting (XSS) 

Cross-site scripting (XSS) attacks insert malicious code into a legitimate web page or web application. When a user visits the site or app, the code automatically runs in the user's web browser, usually stealing sensitive information or redirecting the user to a spoofed, malicious website. Attackers frequently use JavaScript for XSS attacks.

SQL injection

SQL injection attacks use Structured Query Language (SQL) to send malicious commands to a website's or app's backend database. Hackers input the commands through user-facing fields like search bars and login windows. The commands are then passed to the database, prompting it to return private data like credit card numbers or customer details.

DNS tunneling

DNS tunneling hides malicious traffic inside DNS packets, allowing it to bypass firewalls and other security measures. Cybercriminals use DNS tunneling to create secret communication channels, which they can use to silently extract data or establish connections between malware and a command and control (C&C) server.

Zero-day exploits

Zero-day exploits take advantage of zero-day vulnerabilities, which are vulnerabilities either unknown to the security community or identified but not yet patched. These vulnerabilities can exist for days, months, or years before developers learn about the flaws, making them prime targets for hackers.

Fileless attacks

Fileless attacks use vulnerabilities in legitimate software programs to inject malicious code directly into a computer's memory. Cybercriminals often use PowerShell, a scripting tool built into Microsoft Windows operating systems, to run malicious scripts that change configurations or steal passwords.

DNS spoofing

DNS spoofing attacks, also called "DNS poisoning," covertly edit DNS records to replace a website's real IP address with a fake one. When victims try to visit the real site, they're unknowingly delivered to a malicious copy that steals their data or spreads malware. 

Cyberattack prevention, detection, and response

Organizations can reduce cyberattacks by implementing cybersecurity systems and strategies. Cybersecurity is the practice of protecting critical systems and sensitive information from digital attacks by using a combination of technology, people, and processes. 

Preventing cyberattacks

Many organizations implement a threat management strategy to identify and protect their most important assets and resources. Threat management may include policies and security solutions like:

  • Identity and access management (IAM) platforms and policies, including least-privilege access, multi-factor authentication, and strong password policies, can help ensure that only the right people have access to the right resources. Companies may also require remote employees to use virtual private networks (VPNs) when accessing sensitive resources over unsecured wifi.
  • A comprehensive data security platform and data loss prevention (DLP) tools can encrypt sensitive data, monitor its access and usage, and raise alerts when suspicious activity is detected. Organizations can also make regular data backups to minimize damage if there is a breach.

  • Firewalls can help block threat actors from entering the network in the first place. Firewalls can also block malicious traffic flowing out of the network, such as malware attempting to communicate with a command and control server.
  • Security awareness training can help users identify and avoid some of the most common cyberattack vectors, such as phishing and other social engineering attacks.

  • Vulnerability management policies, including patch management schedules and regular penetration testing, can help catch and close vulnerabilities before hackers can exploit them.

  • Attack surface management (ASM) tools can identify, catalog, and remediate potentially vulnerable assets before cyberattackers find them.

  • Unified endpoint management (UEM) tools can enforce security policies and controls around all endpoints on the corporate network, including laptops, desktops, and mobile devices.
Detecting cyberattacks

It is impossible to prevent cyberattack attempts entirely, so organizations may also use continuous security monitoring and early detection processes to identify and flag cyberattacks in progress. Examples include:

  • Security information and event management (SIEM) systems centralize and track alerts from various internal cybersecurity tools, including intrusion detection systems (IDSs), endpoint detection and response systems (EDRs), and other security solutions.

  • Threat intelligence platforms enrich security alerts to help security teams understand the types of cybersecurity threats they may face.

  • Antivirus software can regularly scan computer systems for malicious programs and automatically eradicate identified malware.

  • Proactive threat hunting processes can track down cyberthreats secretly lurking in the network, such as advanced persistent threats (APTs).
Responding to cyberattacks

Organizations may also take steps to ensure an appropriate response to ongoing cyberattacks and other cybersecurity events. Examples include:

  • Incident response plans can help contain and eradicate various kinds of cyberattacks, restore affected systems, and analyze root causes to prevent future attacks. Incident response plans are shown to reduce the overall costs of cyberattacks. According to the Cost of a Data Breach report, organizations with formal incident response teams and plans have 58% lower breach costs on average.

  • Security orchestration, automation, and response (SOAR) solutions can enable security teams to coordinate disparate security tools in semi- or fully automated playbooks for responding to cyberattacks in real-time.

  • Extended detection and response (XDR) solutions integrate security tools and operations across all security layers—users, endpoints, email, applications, networks, cloud workloads, and data. XDRs can help automate complex cyberattack prevention, detection, investigation, and response processes, including proactive threat hunting.
Related solutions
Ransomware protection solutions

To prevent and combat modern ransomware threats, IBM uses insight from 800 TB of threat activity data, information on more than 17 million spam and phishing attacks and reputation data on nearly 1 million malicious IP addresses from a network of 270 million endpoints.

Explore ransomware protection solutions
Resources Cost of a Data Breach report

The Cost of a Data Breach report shares the latest insights into the expanding threat landscape and offers recommendations for how to save time and limit losses.

X-Force Threat Intelligence Index

The IBM Security® X-Force® Threat Intelligence Index offers CISOs, security teams and business leaders actionable insights to help you understand how threat actors are waging attacks, and how to proactively protect your organization.

Top concerns industry leaders have about cyberattacks in 2024 and beyond

Cyberattacks are becoming increasingly sophisticated. Read about the concerns that industry leaders have for the future and three approaches organizations can take to build up their defenses.

Take the next step

IBM cybersecurity services deliver advisory, integration and managed security services and offensive and defensive capabilities. We combine a global team of experts with proprietary and partner technology to co-create tailored security programs that manage risk.

Explore cybersecurity services