Cyber attacks pose a major threat in today’s increasingly digital world. As more sensitive data is stored online and systems become more interconnected, the impact of successful cyber attacks continues to grow. There are many different types of cyber attacks, each with their own goals, tactics, and potential for damage. In this article, we will examine the 5 most common and impactful types of cyber attacks.
1. Malware
Malware, short for “malicious software”, refers to programs designed to infect, damage, and gain control over computer systems. Malware comes in many forms, including viruses, worms, Trojan horses, ransomware, spyware, and adware. Malware often infiltrates networks through email attachments, compromised websites, and removable media. Once inside a system, malware can replicate, spread to other systems, erase data, encrypt files for ransom, spy on users, display unwanted ads, and enable further attacks. Malware can be extremely disruptive, difficult to remove completely, and result in massive financial and reputational damages.
Some of the most impactful malware attacks include:
- The ILOVEYOU virus in 2000 infected over 50 million Windows computers worldwide in a single day, causing billions in damages
- The Conficker worm in 2008 infected millions of computers across 190 countries, causing disruption in hospitals, airlines, government agencies, and more
- The WannaCry ransomware in 2017 encrypted files on over 200,000 computers globally, including critical systems in healthcare, telecoms, and logistics
Defending against malware requires layered security measures like anti-virus software, system updates, user awareness training, and proper network segmentation and access controls.
2. Phishing
Phishing refers to social engineering cyber attacks that trick users into providing sensitive information or unknowingly installing malware. Phishing often starts with authentic-looking emails, texts, phone calls, or websites that pose as trusted entities like banks, online services, or colleagues. Phishing messages attempt to induce victims to click malicious links, download infected attachments, or directly provide personal data like passwords and financial information. Successful phishing can result in identity theft, bank account draining, installation of malware, or system compromise.
Some major phishing schemes include:
- In 2016, hackers used phishing emails posing as Google Docs invites to gain access to Gmail accounts of prominent journalists and Clinton campaign staffers
- The Carbanak cybergang used phishing to infiltrate banks and drain nearly $1 billion from ATMs globally from 2013-2015
- A 2018 phishing scam targeted Office 365 business accounts with fake login pages, compromising over 300,000 email accounts
Phishing prevention requires ongoing user education, email security filtering, multi-factor authentication, and policies forbidding sensitive data sharing.
3. Distributed Denial of Service (DDoS) Attacks
Distributed denial of service (DDoS) attacks aim to overwhelm websites and online services with more traffic than the servers can accommodate, making them inaccessible to legitimate users. DDoS attacks are distributed, meaning the traffic comes from many sources, often a botnet of thousands of compromised devices. Attackers have leveraged massive botnets exceeding 100,000 devices to take down major websites and web infrastructure companies.
Notable DDoS attacks include:
- In 2016, the Mirai botnet of over 100,000 IoT devices took down major sites like Twitter, Spotify, Netflix, and Reddit
- A 2020 DDoS extortion attack generated over 2 terabits per second of traffic, making it the largest ever recorded
- DDoS attacks have repeatedly disrupted Olympic games, including the 2018 Winter Olympics in PyeongChang
DDoS protection requires intelligent traffic inspection, large-scale network capacity, scrubbing centers, and tactics to identify and block botnet traffic.
4. SQL Injection
SQL injection attacks exploit vulnerabilities in web application databases to gain unauthorized access to sensitive data. SQL injections insert malicious SQL code into input fields like login forms to trick the database into executing unintended commands. This allows attackers to view, steal, delete, or corrupt sensitive data. Poorly secured web apps are prone to SQL injection, which can enable data breaches affecting millions of customers.
Major SQL injection breaches include:
- In 2018, over 147 million customers had data stolen from Equifax due to an unpatched SQL injection vulnerability
- Sql injection led to over 77 million user accounts being compromised in Sony’s 2011 PlayStation Network breach
- Ablind SQL injection vulnerability enabled access to over 15 million stolen payment cards in the 2013 Target data breach
SQL injection can be prevented by validating and sanitizing user input, using prepared statements, limiting account permissions, patching vulnerabilities, and closely monitoring traffic for anomalies.
5. Zero-Day Exploits
Zero-day exploits take advantage of software vulnerabilities that are unknown to the vendors. Since the flaws have not been publicly disclosed or patched, attackers can exploit them before defenses are put in place. Criminal hackers and nation-state groups use zero-days to conduct espionage and access sensitive systems. Security experts have uncovered zero-days being actively exploited in the wild for major platforms like iOS, Windows, Android, and Adobe Flash.
Impactful zero-day attacks include:
- Stuxnet, the US-Israeli worm exploiting Windows zero-days to damage Iran’s nuclear program from 2007-2010
- The Elderwood Group’s multi-year campaign exploiting IE and Flash zero-days to hack defense and tech firms
- The Pegasus iOS zero-day enabling remote takeover of phones via iMessage
Defending against zero-days requires constant system monitoring, swift vendor/user notification, and expertise to reverse-engineer exploits. Most regular users must rely on vendors issuing patches once flaws become known.
Defense Against Cyber Attacks
Protecting against the various types of cyber attacks requires a defense-in-depth approach with security across users, networks, and systems. Measures like the following can reduce vulnerability to attack:
- Security awareness training for employees
- Strong password policies and multi-factor authentication
- Regular software patching and system hardening
- Secure network design with firewalls, intrusion prevention, and sandboxing
- Monitoring systems and traffic for anomalies
- Incident response planning and exercises
- Regular backups and disaster recovery capabilities
- Working with ethical hackers to probe and strengthen defenses (red teaming)
No organization can be 100% secure against cyber attacks, but with diligence across technical, procedural, training, and response capabilities, major threats can be minimized.
Conclusion
Malware, phishing, DDoS attacks, SQL injections, and zero-day exploits represent significant cybersecurity challenges today. As digital transformation intensifies across society, individuals and organizations must remain vigilant against emerging attack vectors. By understanding the most impactful attack types, instituting layered defenses, and keeping security top of mind, major threats can be detected and mitigated. With cyber attacks only growing in scale and sophistication, ongoing education, adaptation, and partnerships between governments, vendors, infrastructure providers and end users will be key to creating a safer digital ecosystem.