What Is a Cyber Attack?

What is a cyberattack?

A cyberattack is any action performed to gain unauthorized access to a computer, an information system or an information technology (IT) network to damage, steal, or expose personal or corporate information. An attack could take the form of someone trying to gain access to your LinkedIn account, or it could be more large scale, such as the sophisticated Caesars Entertainment attack that led to the payment of $15 million to hackers to prevent the publication of a customer database.

“For small and medium-sized businesses [SMBs], the best way to think about cyberattacks is as a constant business risk, similar to financial fraud or physical theft,” said Lisa Campbell, vice president, SMB, at CrowdStrike. “Cybercriminals see SMBs as easy targets due to limited security resources, lack of modern protections, and valuable customer or financial data​.”

Any company or individual employee is vulnerable to a cyberattack at any given moment through a mobile device, a laptop computer or a desktop machine. It could come through an email, or it could be a concerted effort targeting corporate servers. But there are also some effective ways you can protect yourself and your business.

“To defend against these threats, SMBs must move beyond basic antivirus and adopt modern security strategies, including device, identity and cloud security, and employee training,” Campbell said. “Cybersecurity is not just about technology — it’s about creating a security-first culture that makes businesses resilient against evolving threats.”

7 most common types of cyberattacks

“SMBs are frequent targets for cybercriminals due to their valuable data and often limited resources for advanced security systems,” Campbell said. While these attacks can come in a variety of forms, these seven approaches are more common than others. 

1. Malware

Malicious software (malware) can come from anywhere and take any form. These malicious applications can enter an IT network simply by opening an email attachment or installing an EXE file from a suspicious site. Once malware gets into your system, it isn’t easy to contain.

Malware comes in many forms, such as spyware, ransomware, keyloggers and viruses. For example, ransomware is used to bar access to computer systems and data, only restoring them upon payment of a sum of money. This happened to the IT group CDW, which fell victim to an attack. Their hackers demanded a ransom of $80 million. The company offered them $1.1 million, which was rejected, so the attackers started to leak CDW’s data.

2. Phishing

A phishing attack is a message intended to trick someone into revealing personally identifiable information (PII) that would give access to your accounts. Phishing attacks used to be easy to spot — like those emails from a foreign prince who wants to give you millions of dollars. That’s a phishing scam to get your bank account information.

This type of cyberattack has become more sophisticated in recent years, coming from email servers spoofing official corporate email addresses, applications on hijacked web pages or even phone calls from criminals claiming to be government officials. For the most part, these types of attacks tend to focus on fear or greed, so if something seems too good to be true, it should be treated with caution. [Related article: Using Machine Learning to Detect Spear Phishing Attacks]

“One of the most common threats facing SMBs is business email compromise (BEC),” said Andy Piazza, senior director, threat intelligence at Palo Alto Networks’ Unit 42. “These phishing attacks typically involve a bad actor using a compromised or spoofed email — often appearing to come from a trusted third-party partner — to trick your employees into actions like rerouting invoice payments to fraudulent accounts with the goal to steal funds without ever needing to breach your systems directly.”

3. Distributed Denial-of-Service (DDoS) attack

A DDoS attack gives cybercriminals a way to overload a network with unwanted traffic that eventually overwhelms and disrupts live services. It’s like a crowd blocking you from your favorite store, preventing anyone from going in and keeping away a business’s actual customers. These types of targeted attacks usually focus on larger organizations, including banks and other financial gateways, essentially allowing hackers to ruin those companies.

4. Structured Query Language (SQL) injection

A SQL injection allows a hacker to exploit weak web forms by using malicious commands to steal data, delete or modify records, or even take over an entire website — all through a relatively simple process. An SQL exploit is often considered one of the more avoidable breaches because it usually comes from broken code on a database or a website. Through trial and error, a skilled cybercriminal could access customer information like credit card numbers, home addresses and email addresses.

5. Zero-day exploit

One of the more effective types of cyberattack is the zero-day exploit, which is a recently discovered bug or vulnerability that can be easily used to attack, overwhelm or take over a system. Once a zero-day exploit is discovered, the clock starts ticking. Worst of all, some zero-day exploits may not be discovered by corporate IT departments for weeks or months after the first breach.

6. Compromised credentials

These attacks involve cybercriminals obtaining and using legitimate passwords and usernames. These credentials may have been stolen in phishing attacks, leaked during a data breach or acquired in some other fashion. However they are obtained, they are used to access systems without authorization, granting attackers seemingly legitimate access to accounts and resources. 

“In our remote world where employees can access company data from anywhere, we are seeing a rise in identity-based attacks,” said Matt Caulfield, vice president of Identity and Duo, Cisco Security. “An identity-based attack targets an individual’s or organization’s identity credentials, such as usernames, passwords or other authentication information, to gain unauthorized access to systems, networks or data.”

7. Insider threats

These attacks occur when trusted individuals within an organization cause harm internally, either intentionally or unintentionally. These attacks are often related to access misuse and could lead to data breaches, installation of malware or other threats. 

5 most damaging effects of a cyberattack

“Overall, the risks following a cyberattack are multifaceted and can have long-lasting effects on a business’s financial health, operational stability and reputation,” Caulfield said. “Taking proactive measures to secure data and prevent breaches is crucial for minimizing these risks.”

Some of the most damaging impacts on your business include the following. 

1. Financial loss

Some cyberattacks focus on the actual theft of corporate funds, while others end up costing a company scores of cash, simply as a side effect. According to IBM, the average cost of a data breach caused by a cyberattack is around $4.88 million.

A simple data breach can quickly become a devastating financial loss for any business. The costs associated with your IT managers updating the security protocols for the entire corporate network, as well as the physical security of individual worksites, can add up remarkably fast. 

2. A tarnished reputation

Everyone says, “I never thought it would happen to me.” But this is what hackers rely on — nobody expects a cyberattack. That’s why they’re so effective.

Customer trust becomes a real concern after an attack; potential customers and clients might scrutinize the losses and gaps in security, which could lead to lost business. “The reputation impact can be severe,” Piazza noted. “If you’re compromised, will your business partners want to continue working with you or trust you? Can your company survive losing a trusted third-party relationship like a critical vendor?”

3. Extensive business disruptions

Once a cybercriminal successfully breaches a corporate network, there are multiple ways they could overwhelm your business. One cyberattack may focus solely on siphoning funds, while another might attempt to disrupt a supply chain. Other attacks, like a DDoS attack, may focus on overwhelming your system to cause the failure of each service or application you offer. Recovering from a cyberattack could take days or even weeks and could cost millions.

4. Legal liabilities

After any major data breach, an organization must prove its compliance with any state, federal or regulatory standards for its specific industry. Companies that keep meticulous records and conduct regular audits should have a paper trail that shows that all the required steps were followed. 

For companies that don’t keep such thorough records, legal fees could add up. Worse yet, even if a business followed all the rules and regulations, clients and partners could still pursue legal action when a data breach includes certain information. “SMBs handling sensitive data also risk legal and compliance penalties if they fail to protect customer information,” Campbell noted.

5. Data loss

Perhaps the most destructive effect of a cyberattack is the loss of sensitive corporate data. In addition to personal and sensitive customer data, a well-executed attack could reveal other information, like patents, commercial secrets and the source code of major products. Once a cybercriminal has that kind of company information, they have a lot of power.

With the source code of an application, a cybercriminal has all they need to break the software outright or weave in vulnerabilities to exploit unsuspecting users. Users could potentially reveal other flaws in their own network that a cybercriminal could utilize, unintentionally giving a cyberattack a way to increase the damage it causes. That’s when a business becomes liable — potentially leading to financial loss, a damaged reputation and a laundry list of legal ramifications.

How to prevent a cyberattack against your business

Cyberattacks can cause extensive damage and reputational loss to businesses of any size. “SMBs have a unique challenge compared to large enterprises —fewer resources for security staffing and tools,” Piazza said. “But that doesn’t mean they’re powerless. There are cost-effective ways that SMBs can raise defenses against attacks.” 

While it is impossible to bring the risk of an attack to zero, there are several immediate steps businesses can take to make themselves a more difficult target. 

Enforce strong password security practices.

Believe it or not, people still use remarkably weak passwords for their various accounts. According to Security.org, the most common password today is “123456.” A strong password is the first line of defense against a cyberattack.

Some best practices for passwords include using at least one numeral and one special character, like a hashtag or a question mark. Other recommended practices are using a unique password for every account you have, changing those passwords regularly and using a password manager.

Accounts should also be protected with multi-factor authentication (MFA) tokens whenever possible, Piazza advised. “These devices are cost-effective, easier to implement for an SMB than a large enterprise and extremely effective at preventing unauthorized access,” he said. “At a minimum, SMBs should consider adopting physical MFA for their system administrators, IT personnel and executives — those with access to your most critical systems.”

Always use the latest software.

Cybercriminals use exploits like a zero-day attack through older versions of an application, and all types are vulnerable, from an email program to a media player to an instant messenger. Many application updates include security fortifications to shore up known issues and prevent similar bugs from being exploited in a future cyberattack. If you’re running the latest versions of your software packages and apps, they’re probably secure.

Use a virtual private network (VPN).

When your business is equipped with a top VPN, you get a direct pipeline to your network through the internet that keeps your information hidden from prying eyes. 

A VPN filters your traffic through various servers to hide your activity or location from cybercriminals and even your internet service provider. While there are some drawbacks to even the best VPN, such as slower network speeds and internet protocol blacklisting, the benefits, such as added security, anonymity and access to georestricted content, outweigh them. [Related article: Secure Remote Access: What It Is and How It Works]

Use a reliable cybersecurity insurance service.

Cybersecurity insurance can help any business recover from the effects of a successful cyberattack, whether it’s financial assistance, logistical support or additional IT resources. Once a breach occurs and exposes employee or customer PII, a cybersecurity insurance policy will activate and help notify the necessary parties of the incident while helping mitigate the company’s liability.

Cybersecurity insurance policies can cover fraud and theft, as well as the forensic work necessary to expose a network’s weaknesses and help prevent future incidents. These types of policies can also help recover extorted funds and assist with the loss and restoration of data.

Backup and encrypt your data regularly.

Have you ever forgotten to save a document before you closed it? It’s awful to lose all the work you put in because of a moment of absentmindedness. Now, imagine you saved all of your data, but it’s all been deleted by a rampaging hacker who wants to do harm. It’s even worse to lose all that work because of a targeted attack. The good news is that it’s perfectly preventable with a cloud-based document management system.

By backing up your data to an encrypted location regularly, you not only add security to your corporate documents but also protect them from being deleted permanently. If you keep multiple copies of your documents on a secure server or an external drive, it stops hackers from finding them in the first place. [Related article: Cloud Encryption: Using Data Encryption in the Cloud]

Invest in an identity solution. 

As more and more cyberattacks employ identity-based attacks, organizations need to invest in identity solutions. These solutions help prevent the misuse of compromised credentials. This pays dividends in preventing a range of damaging attack types, including data breaches and ransomware. 

“Investing in an identity solution is crucial for businesses of all sizes, as compromised credentials are a primary entry point for ransomware attacks,” Caulfield said. “MFA is a key component of identity security, requiring multiple forms of verification such as passwords, tokens or biometrics to reduce the risk of unauthorized access.”

Why do cyberattacks happen?

Cyberattacks occur for a variety of reasons and are perpetrated by many actors. Below, we look at why attacks occur, what these attacks target and who’s behind them.

Why?

The three main reasons cyberattacks occur are criminal, political and for other reasons.

1. Criminal

Cybercriminals can be motivated by:

• Direct theft, such as stealing money from bank accounts
• Identity theft, such as the sale of personal and financial information on the black market to fraudsters
• Extortion, such as the use of ransomware or DDoS attacks to force victims to pay to regain access to their systems or data
• Corporate espionage, such as hacking into a company’s research and development department to gain insight into a competitor’s activities

2. Political

Countries might use cyberattacks to:

• Destabilize another state, such as by targeting its financial markets, energy grids and other systems
• Obtain knowledge, such as to influence political outcomes or to reveal secretive communications and strategies
• Kompromat, such as to obtain damaging information on a person or group to discredit or blackmail them

Other situations in which political cyberattacks occur include:

• Public exposure, such as hacktivists releasing confidential information to expose human rights abuses and corruption
• Reputation damage, such as targeting a political party or other entity to uncover and publicize embarrassing information to undermine public trust
• Raising public awareness, such as hacking into government websites, media outlets or corporations to discover information to support an individual’s or organization’s perspective.

3. Other

Three other main reasons behind individual cyberattacks include:

• Revenge, such as employees stealing data to sell to competitors
• Competition, such as overcoming the challenge of breaking into difficult-to-penetrate systems before other hackers
• Penetration testing, such as when companies employ contractors to attempt to hack into their systems to identify vulnerabilities

What?

The primary targets in a cyberattack are:

• Financial assets: This could be the theft of cash or other financial instruments from bank accounts, digital wallets and online financial services.
• Financial data: Hackers often steal credit card information, banking details and other financial records, quickly selling them on the black market.
• Personal data: This could be Social Security numbers, phone numbers, addresses and so on that could be used to set up fake credit profiles to apply for loans.
• Sensitive data: This may include health records, private communications and legal documents that could be used to blackmail an individual or company. Health records may be sold for marketing purposes. [Related article: How  Health Insurance Portability and Accountability Act Laws Impact Employers]
• Corporate information: This is intellectual property, like trade secrets, business strategies, ongoing research and development projects, proprietary technology and future business strategy.
• Infrastructure: This is when communications networks, transport systems and power grids are attacked.

Who?

Perpetrators of cybercrime can be external or internal. The primary external threats are:

• Organized crime: Sophisticated groups of criminals will target individuals, companies and networks for financial gain.
• State actors: Nation-states will attack each other’s infrastructures, elections and so on for political reasons.
• Amateur hackers: Some see hacking as a challenge and may target individual systems to improve their skills.
• Hacktivists: Hacktivists are motivated by ideological and political purposes to carry out attacks but are usually not sponsored by individual states.

Key internal threats include:

• Employees: Employees, especially disgruntled current or former employees who still have access to company systems, may steal data or sabotage your network.
• Contractors: Although rare, an independent contractor with a grievance toward their client may be motivated to damage their IT system and access their data without consent.
• Business partners: In situations where there is a fallout between shareholders, an individual may attempt to access information available to other shareholders beyond that permitted by any partnership agreement. They may do this to gain a competitive advantage in negotiating an exit.
• Clients: In case of a commercial dispute or in an attempt to gain a bargaining advantage, a client may attempt to access a supplier’s IT system for commercially sensitive information.

As you can see, modern businesses face multiple cybersecurity issues. However, unless you’re an international business or a key supplier to multinational companies or governments, you are exceedingly unlikely to be targeted by rogue nations and hacktivists.

You shouldn’t think, though, that as an owner of an SMB, your business and its data would not interest cyberattackers. According to penetration testing company PacketLabs, 43 percent of cyberattacks target SMBs.

“SMBs are likely to face attacks from cybercriminals looking for quick and easy wins,” Campbell said. “Unlike large enterprises, most SMBs don’t have 24/7 security monitoring, making it harder to detect and stop an attack in real time. Many also lack the resources for a rapid incident response, meaning a breach could linger undetected for weeks.”

What are examples of well-known cyberattacks?

Recent examples of successful cyberattacks include:

• In December 2022, United Kingdom newspaper The Guardian was hit by a ransomware attack that affected its operation for months.
• In January 2023, a hacker leaked more than 220 million users’ email addresses from Twitter, now known as X.
• In September 2023, Casino chain Caesars Entertainment paid $15 million to hackers so they wouldn’t publish a database of loyal customers they’d stolen.
• UK logistics firm KNP Logistics declared itself insolvent in September 2023 following a ransomware attack, causing 700 employees to lose their jobs.
• In September 2023, British digital protection firm DarkBeam suffered a data breach affecting in excess of 3.8 billion records.
• In December 2023, cybersecurity researchers discovered online education platform Real Estate Wealth Network had more than 1.5 billion personal real estate ownership records exposed, including those of celebrities and politicians.
• In March 2024, Canada had to pull its financial intelligence system FINTRAC offline after hackers caused a cyberincident relating to the system. 
• In May 2024, United States-based health system company Ascension was hit by a ransomware attack that affected 5.6 million people through the theft of personal information such as Social Security numbers, medical and payment information and insurance details. 
• In January 2025, hackers claimed to have stolen 62.4 million student records and 9.5 million teacher records, which could include Social Security numbers, home addresses and medical information, from the education company PowerSchool.

Jeremy Bender and Eduardo Vasconcellos contributed to this article.