Knowledge What Is a Cyberattack? Main Types, Techniques, and Measures Companies Should Implement Immediately

Cyberattacks are no longer merely an IT issue; they pose a risk that can threaten a company’s very existence.

First, we explain what constitutes a cyberattack and why countermeasures are so urgent now.

A cyberattack is a catch-all term for acts carried out via networks such as the Internet to illicitly access corporate computer systems—servers, PCs, smartphones—and steal, alter, or destroy data.

It also includes actions that halt systems and disrupt operations. Attackers cleverly exploit system vulnerabilities and human psychology, using a variety of tactics.

With the advance of digital transformation (DX) and the spread of remote work, companies’ IT usage has expanded rapidly.

Cyberattacks grow more sophisticated and malicious, neglecting countermeasures can be fatal to business continuity.

What motivates attackers to carry out cyberattacks? While their aims vary widely, they generally fall into the following four categories.

The most common objective is monetary profit. Methods include encrypting data with ransomware and demanding a ransom, stealing online banking credentials to make unauthorized transfers, and illicit use of credit card information. These tactics are direct and diverse.

Corporate trade secrets, customer data, and employees’ personal information are prime targets. Stolen data may be traded on the dark web or passed to competitors, significantly undermining a company’s competitiveness. Personal information leaks can also lead to compensation claims and reputational damage.

Attacker groups (hacktivists) backed by certain states or ideologies may deface government or large corporate websites or knock services offline to publicize their beliefs. Recently, amid rising geopolitical tensions, attacks targeting critical infrastructure have also been observed.

Individuals with grudges against specific organizations may attack to harass or disrupt operations. A representative tactic is DDoS, which floods websites or servers with traffic to stop services, inflicting significant economic harm.

Cyberattack techniques evolve daily. Based on sources such as the Information-technology Promotion Agency (IPA)’s “Top 10 Information Security Threats 2024,” here are representative attacks that companies should especially watch out for.

Ransomware encrypts data on corporate servers and PCs and holds it hostage to demand a ransom.

Recently, “double extortion”—threatening to publish stolen data if no ransom is paid—has become mainstream, worsening the impact.

Instead of attacking the target company directly, attackers use comparatively weaker security at suppliers, subsidiaries, or external services used in operations as a stepping stone to infiltrate the target.

Even if your own defenses are strong, you risk attack if the entire supply chain is not secured.

Attackers send emails to specific employees that appear relevant to their work or pretend to be from business partners. By inducing recipients to open attachments or click URLs, they infect systems with malware.

Such emails are increasingly sophisticated and difficult to detect at a glance.

These attacks exploit flaws (vulnerabilities) in software and applications that power websites.

Representative examples include SQL injection, which executes unauthorized commands against databases, and cross-site scripting, which embeds malicious scripts in pages—both can lead to data leaks or site defacement.

A “DoS attack” overwhelms a target server with requests from a single computer, while a “DDoS attack” mounts a distributed assault from multiple computers.

If an e-commerce or similar site is targeted, services may be interrupted, leading to direct losses such as missed sales opportunities.

A cyberattack in which fraudulent emails are sent impersonating employees of a targeted organization or its business partners, with the aim of tricking victims into transferring funds to fake bank accounts. In recent years, attacks leveraging generative AI have been increasing, making these schemes more sophisticated.

No single measure is sufficient to protect companies from increasingly sophisticated attacks. A multilayered defense combining organizational measures and technical measures is essential.

Start by clearly defining a company-wide basic policy (security policy) for information security.

Document concrete rules for handling information, password management, and incident reporting flows, and ensure thorough company-wide awareness.

Many cyberattacks exploit human weaknesses such as carelessness and lack of knowledge.

Regularly conduct security training to build practical knowledge, such as how to spot suspicious emails and set strong passwords.

Simulated targeted email exercises are also effective.

In addition to traditional antivirus software, it is advisable to deploy EDR (Endpoint Detection and Response), which detects and responds to suspicious activity on PCs and servers.

This allows containment before damage spreads, even if malware slips through initial defenses.

Enforce the principle of least privilege by granting each employee account only the minimum access rights required for their job.

This limits damage even if an account is compromised. Also ensure rigorous account lifecycle management, such as promptly deleting accounts of departing employees.

Keep operating systems and all software on PCs up to date.

Apply security patches from vendors promptly to fix known flaws—leaving vulnerabilities unpatched is a fundamental cause of compromise.

No matter how many defenses you put in place, you cannot reduce the risk to zero. What matters is how quickly and calmly you act when an incident occurs.

Upon discovering damage, first physically disconnect potentially affected PCs or servers from the network to prevent spread.

Next, promptly report to the IT department or the predesignated incident response team and follow their guidance. Avoid rebooting devices or deleting suspicious files on your own, as doing so may destroy evidence and hinder subsequent investigations.

Depending on the situation, promptly report to relevant authorities. In Japan, if personal information has been leaked, one must report to the Personal Information Protection Commission.

If you have been a victim of cybercrime, consult your local police station or the prefectural police cybercrime consultation desk. Contact your cyber insurance provider and specialized forensics firms as needed.

After emergency measures, thoroughly investigate why the attack succeeded.

With help from external experts as needed, identify the intrusion path and scope of damage, and develop and implement concrete measures to prevent recurrence.

This article has provided a comprehensive explanation of cyberattacks—their definition, objectives, types, and the measures companies should take. Cyberattacks are growing more sophisticated by the day, and their threats are increasing. However, by correctly understanding the risks and implementing multilayered organizational and technical countermeasures, you can significantly reduce exposure.

Security is not a one-and-done effort. Ongoing information gathering and periodic reviews of your defenses are essential to keep pace with evolving threats and to safeguard your company’s sustainable growth and trust. 

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