The Largest and Most Notorious Cyber Attacks in History

Introduction to Cyber Attacks: Understanding the Global Threat

Cyber attacks are deliberate attempts to steal, alter, or destroy data or to disrupt operations and to damage the digital parts of a critical infrastructure. This blog post explores the most destructive major cyber attacks in history, detailing the underlying motives and impact, and then offers prevention and detection best practices.

Types of Cyber Attacks

Cyber attacks come in many forms, including the following:

• Malware — This is the general name for malicious software that infiltrates systems to inflict damage or steal data. Examples include viruses, worms and spyware.
• Ransomware — Ransomware is a type of malware that encrypts a victim’s files or systems, rendering them inaccessible. The attacker then demands a ransom payment, often in cryptocurrency, in exchange for the decryption key or a promise to restore access.
• Phishing — Malicious actors attempt to collect sensitive information by impersonating a legitimate entity through email. Related attacks use text messages (smishing), voice calls or voicemails (vishing), or falsifying QR codes (quishing). In essence, anything that requires user interaction is a potential vector for attackers.
• Social engineering — Attackers exploit human traits like trust, fear, curiosity or urgency to deceive individuals into divulging sensitive information, granting unauthorized access or performing other actions that compromise security.
• Denial-of-service (DoS) attacks — In a DoS attack, adversaries attempt to flood a system or network with such high traffic that it becomes inaccessible to legitimate users.
• Man-in-the-Middle (MITM) attacks — Attackers intercept communication between two parties to steal data or inject malicious code.
• SQL injection — Attackers exploit vulnerabilities in a database-driven website to gain unauthorized access to data.
• Zero-day exploits — Adversaries work hard to uncover and exploit cybersecurity vulnerabilities in software or hardware before the vendor finds them and issues a patch.

It is important to understand that a cyber attack almost always involves a combination of the attack methods listed above used along the attack path. Think of scenarios like the following: phishing and social engineering are used to collect valid credentials from unsuspecting users so that the attackers can use them to infiltrate the target system. To go undetected while making their way into the network, they launch a DoS attack to distract the defenders, and in a move to dig even deeper, they will attempt to use known vulnerabilities to conquer critical systems.

Underlying Motives

Motivating factors behind cyber attacks include the following:

• Financial gain — Malicious actors monetize attacks in multiple ways. For instance, they steal personal information, financial data or intellectual property to sell on the black market; demand ransoms in ransomware attacks; or using smishing or vishing to convince employees to transfer money to them.
• Political or ideological motives — Sometimes, the motive is to disrupt services or damage an organization’s reputation because of political or ideological disagreements.
• Furthering national interest — Countries use cyber warfare to target government agencies, defense systems and critical infrastructure to gather intelligence or disrupt operations.
• Corporate espionage — Companies may engage in cyber attacks to steal a competitor’s trade secrets, research or other proprietary information.
• Ego — Some attackers launch cyber attacks to demonstrate their skills, build a reputation within hacking circles or test their abilities.

Impact of Cyber Attacks

The damage from cyber attacks can extend far beyond the immediate target to affect communities, economies and international relations. In 2015, when writing a report for the World Economic Forum, researchers at McKinsey expected the cost of cyber crime (or loss in economic value) to be at $3 trillion in 2020, whereas in 2020 the predicted loss for 2025 rose to $10.5 trillion, and the current predictions for 2029 are around $15 trillion.  

But financial damage is not the only result. Below are some of the other key impacts of attacks on critical infrastructure (like power grids, healthcare agencies and water treatment systems), governments and corporations.

Impact of Attacks on Critical Infrastructure

• Public safety risks — Cyber attacks can cause service outages that disrupt daily life or even endanger lives.
• Erosion of public trust — Frequent or severe attacks on critical infrastructure can undermine public trust in the government’s ability to provide safe, reliable services.

Impact of Attacks on Governments

• National security risks — Theft of classified information such as military intelligence or damage to defense systems and communication networks can weaken a country’s defense posture.
• Public safety risks — Disruptions to government operations can cripple crucial services, such as emergency response systems and payments to vulnerable populations.
• Political damage — Cyber attacks and disinformation campaigns are increasingly being used to influence election results, manipulate public opinion, and create unrest.

Impact of Attacks on Corporations

• Reputational damage and lost revenue — A breach can erode customer trust, resulting in lost business. It can also damage partner and supply chain relationships.
• Loss of competitive edge — Theft of proprietary information like trade secrets and research can weaken a company’s competitive stance.
• Compliance penalties — A breach of regulated data can result in steep penalties, increased scrutiny during future audits and even restrictions on core business operations like taking credit card payments.

The Special Case of Cyber Warfare

Cyber warfare warrants special discussion. Nation-states employ advanced cyber capabilities to pursue strategic, political and economic goals on a global stage, with the intention of undermining adversaries or gaining a competitive advantage. Indeed, cyber warfare has escalated geopolitical tensions and created an environment where robust cyber defensive and offensive capabilities are an essential part of national security strategy.

Key aspects of cyber warfare include:

• Espionage — Many nation-states using cyber attacks to gather intelligence regarding political strategies, technological advancements, economic trends and more.
• Infrastructure attacks — States also target critical infrastructure like energy grids, health systems and financial institutions to display their power or destabilize opponents.
• Disinformation — Another cyberwar tactic is to spread disinformation through social media to influence other countries’ politics, creating social and political instability. This includes efforts to sway public opinion or manipulate electoral processes.
• Economic sabotage — Nation-states may steal intellectual property or undermine corporate and government operations in order to damage an adversary’s economy and weaken its position in the global economy.
• Use of proxy actors — Nation-states often sponsor hacking groups, private contractors and other third parties to perform cyber operations on their behalf. This approach helps them deny responsibility and avoid consequences.

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Historical Overview: The Most Notorious Cyber Attacks in History

Evolution of Cyber Attacks

Over the years, cyber attacks have become more complex, sophisticated and destructive. Here is a brief history:

• Early days (1970s–1980s) — The earliest cyber threats were basic viruses and worms, mostly created for experiments.
• The rise of malware (1990s) — As personal computers became common, viruses, Trojans and email worms started appearing, spreading through email attachments and floppy disks.
• Financially motivated attacks (2000s) — This period saw an explosion in spyware, phishing, social engineering campaigns. Adversaries also began creating networks of infected computers (botnets) to launch distributed denial of service (DDoS) attacks.
• Organized cybercrime and APTs (2010s) — Next came a barrage of ransomware attacks such as CryptoLocker and WannaCry. Nations and other groups began using advanced persistent threats (APTs) to infiltrate systems while staying undetected and stealing data over time. Moreover, hackers exploited vulnerabilities in IoT devices to gain unauthorized access or control networks.
• Modern threats (2020s) — Recent years have seen the bar to cybercrime lowered. For example, ransomware-as-a-service (RaaS) offerings now facilitate attacks with ransomware kits and services, and AI-based tools enable amateurs to create deepfakes to deceive or manipulate targets. Another trend is supply chain attacks like SolarWinds, where software or hardware suppliers are targeted as a doorway to infiltrate the systems of their customers. Direct attacks on critical infrastructure like health systems have also increased.

A Timeline of Major Cyber Attacks

Three of the Biggest Cyber Attacks of All Time

Below are some of the biggest cyber attacks in history.

WannaCry (2017)

The WannaCry attack in May 2017 infected individual users and large organizations worldwide with ransomware. The US and the UK attributed the attack to North Korea’s Lazarus Group.

• Background — In April, a hacking group called Shadow Brokers leaked some tools allegedly developed by the US National Security Agency (NSA), including EternalBlue, the exploit used in the WannaCry attack. Microsoft had already released a security patch to fix the vulnerability abused by EternalBlue, but many organizations did not promptly apply this critical update.
• Methodology — The ransomware spread through phishing emails or direct exploitation of the EternalBlue vulnerability in unpatched systems. It used a worm-like mechanism to spread across networks. Then it encrypted files and demanded payment for decryption keys. The initial ransom amount was $300 in Bitcoin per device, which increased if payment was not made within a specified time.
• Response — A security researcher quickly discovered a kill switch in the ransomware code, halting its spread by registering an unregistered domain hard-coded into the malware. However, organizations were urged to apply the Microsoft patches and strengthen their cybersecurity defenses.
• Impact — The attack affected over 200,000 devices in 150 countries, with the healthcare, transportation, banking and telecommunications sectors hit hard. For example, many hospitals and clinics under the UK National Health Service (NHS) were paralyzed, with thousands of appointments cancelled and medical procedures delayed. The damage was estimated to be $4 billion–$8 billion.
• Lessons learned — The incident underscored the importance of regular system backups, robust endpoint protection, and employee training.

Yahoo (2014)

A 2014 data breach at Yahoo exposed the data of over 500 million users; however, the breach was not publicly disclosed until two years later. The US attributed the crime to four individuals, including two hackers allegedly linked to Russia’s Federal Security Service. An earlier 2013 breach had compromised all 3 billion Yahoo accounts.

• Methodology — It is believed that the attackers employed spear-phishing and possibly other techniques to infiltrate Yahoo’s systems. They then gained access to the data of 500 million users, including their names, email addresses, passwords hashed using a weak algorithm, dates of birth, phone numbers, and security questions and answers.
• Response — Users were advised to reset their passwords, implement multifactor authentication (MFA) and monitor their accounts for suspicious activity. Yahoo had to work on improving its cybersecurity practices, including upgrading encryption standards and adopting more robust intrusion detection capabilities.
• Impact — Combined, the 2013 and 2014 breaches stand out as the largest data breaches in history. Millions of users faced a high risk of identity theft, phishing and other cybercrimes because their personal information was exposed. The breach eroded user trust and damaged Yahoo’s reputation, as the company faced lawsuits, regulatory scrutiny, and settlements totaling hundreds of millions of dollars. Verizon acquired Yahoo in 2017, with the breaches reducing the acquisition price by $350 million.
• Lessons learned — Yahoo faced criticism for not disclosing the incident until two years later  leading to calls for stricter data breach notification laws. It also highlighted the need for comprehensive data protection regulations, such as the GDPR, to enforce accountability and safeguard user information.

Ukraine Power Grid (2015)

A 2015 attack in Ukraine was the first cyber attack to shut down a nation’s electrical power supply. The attack is believed to have been staged by Sandworm, a Russian hacking group.

• Methodology — They gained access to the network through phishing emails containing malware called BlackEnergy 3. Next, they used the malware to perform reconnaissance and move laterally to identify critical systems and gather credentials for accessing the Supervisory Control and Data Acquisition (SCADA) systems. Using the stolen credentials, they remotely issued commands to open circuit breakers, disconnecting power to substations.
• Impact — Some 230,000 residents lost power for up to 6 hours. Services such as hospitals and transportation systems were also temporarily disrupted.
• Response — To slow response, the attackers deployed KillDisk malware to overwrite firmware and render devices inoperable and launched a telephone denial-of-service attack on customer service lines to prevent users from reporting outages. The energy companies had to rely on manual processes for days, and since the attackers had disabled remote capabilities, field crews had to manually operate the circuit breakers to restore power. Affected systems were rebuilt or restored from backups.
• Lessons learned — The energy companies took steps to isolate critical systems from public networks and enhance employee awareness about phishing. More broadly, the incident showcased how vulnerable critical infrastructure can be to APTs and the growing risks of cyber warfare.

Recent Major Cyber Attacks 

Some biggest cyber attacks in the last five years are discussed below.

MOVEit (2023)

In 2023, a Russian-speaking cybercriminal group called Clop exploited a vulnerability in MOVEit Transfer software to steal massive amounts of data.

• Methodology — By exploiting a software vulnerability (CVE-2023-34362) and deploying a web shell named LEMURLOOT, the group was able to execute unauthorized SQL commands and exfiltrate data. They threatened to publish the stolen data unless a ransom was paid.
• Response — Progress Software released patches to address the vulnerability immediately upon its discovery. Organizations were advised to apply software patches, scan systems for indicators of compromise (IOCs), and update security configurations.
• Impact — Over 2,500 organizations were impacted, including Amazon, the BBC, British Airways, Shell and the New York City Department of Education. The incident exposed the sensitive data of some 60 million individuals, including personally identifiable information (PII), financial data and internal communications.

Colonial Pipeline (2021)

On May 7, 2021, Colonial Pipeline suffered a ransomware attack that disrupted fuel supplies across the East Coast. DarkSide, a cybercriminal group believed to be based in Eastern Europe, perpetrated the attack.

• Methodology — The attackers gained initial access using a compromised password for a VPN account that did not have MFA enabled, which investigators believe was obtained from a dark web database. They then stole 100 gigabytes of data and deployed ransomware to encrypt Colonial Pipeline’s business network systems.
• Response — While the operational technology (OT) systems were not directly affected, the company shut down operations as a precaution. Then it paid the ransomware operators a ransom of about 75 Bitcoin, or nearly $5 million. However, the decryption tool provided by the attackers was reportedly slow and inefficient, and the company had to work with cybersecurity experts to restore operations. In June 2021, the Department of Justice (DOJ) recovered $2.3 million of the ransom payment by tracking the Bitcoin wallet.
• Impact — Colonial Pipeline supplies nearly 45% of the East Coast’s fuel, including gasoline, diesel and jet fuel. Operations were shut down for several days as a result of the attack, which caused widespread fuel shortages and panic in the southeastern United States. The US government declared a state of emergency to mitigate the impact of the fuel shortage.

SolarWinds (2020)

In December 2020, it was revealed that the IT management company SolarWinds had been compromised in a supply chain attack. Hackers infiltrated SolarWinds’ systems and inserted malicious code into the updates for their Orion software platform, which is widely used for IT monitoring and management. Over 18,000 SolarWinds customers downloaded the compromised software update, giving attackers a potential backdoor into their systems to commit espionage. The attack is attributed to a threat group  often linked to Russia’s Foreign Intelligence Service (SVR).

• Methodology —The attackers exploited flaws in Microsoft products, services and software distribution infrastructure. For example, they abused the Zerologon vulnerability to access credentials in the networks they breached, which in turn enabled them to compromise Office 365 email accounts. Another software flaw may have allowed them to bypass MFA.
• Response — The security community delivered tools for determining which customers had been breached, a kill switch for the malware used in the attack, countermeasures for potential abuse of software stolen from customers, and more.
• Impact — This supply chain attack affected multiple US government agencies, including the Department of Homeland Security (DHS), the Department of the Treasury, and the Department of Commerce. It also affected thousands of private organizations globally, including Microsoft. SolarWinds investors filed a class action lawsuit related to its security failures and the subsequent fall in share price.

Worst Cyber Attacks in the Government and Defense Sectors

Below are the worst cyber attacks in history related to the government and defense sectors.

SQL Slammer (2003)

The SQL Slammer worm was one of the fastest-spreading malware attacks in history. Exploiting a known vulnerability in Microsoft SQL Server, the worm infected vulnerable systems within minutes and spread exponentially without requiring user interaction. Its rapid propagation caused widespread disruptions, including outages in ATMs, airline systems, and emergency response services.

Although it did not steal data, the worm generated massive amounts of network traffic, effectively launching a denial-of-service attack. The aftermath prompted organizations worldwide to prioritize patch management and highlighted the critical importance of timely software updates to protect against known vulnerabilities.

Russia-Ukraine Cyber Warfare (2022 and later)

The Russia-Ukraine conflict has been marked by significant cyber warfare. Prior to and during its invasion of Ukraine, Russia launched multiple cyber attacks targeting Ukrainian infrastructure, some of which the International Criminal Court (ICC) is investigating as possible war crimes. For example, a 2022 cyber attack compromised over 70 Ukrainian government websites, and additional operations targeted both the Ukrainian government and banking websites, leading to significant disruptions. Russia has also attempted to disrupt Ukraine’s power grid through cyber means, aiming to create widespread outages and chaos.

Ukraine has responded with both offensive and defensive cyber strategies. In particular, a volunteer cyber began targeting Russia government websites and financial institutions, and allied nations have provided intelligence and technical support to bolster cyber defenses.

These events underscore the critical role of cyber warfare in modern conflicts and highlights the need for robust cybersecurity measures and international cooperation.

US Office of Personnel Management (OPM) (2014)

The US OPM suffered one of the most extensive breaches of government data in US history. Attackers used credentials stolen from a subcontractor to gain access to OPM’s systems. It later came to light that they had maintained access to OPM’s systems for almost a year.

Some 22.1 million individuals, including federal employees and contractors, were affected. The breached data included names, Social Security numbers and fingerprint data, as well as security clearance information such as data about family members, roommates, foreign contacts, and psychological information.

OPM offered credit monitoring and identity theft protection services to those affected, and the OPM’s Director and Chief Information Officer both had to resign.

The Impact of Cyber Attacks on Corporations

Marriott (2018)

In November 2018, Marriott International disclosed a massive data breach that began in 2014 at Starwood, a company that Marriott acquired in 2016 but had not yet migrated to its own reservation system. Cybersecurity experts believe that state-sponsored actors, possibly from China, were responsible for the breach, in part because the compromised data would be useful for foreign intelligence agencies.

• Methodology — Investigations revealed that attackers had installed malware, including Remote Access Trojans (RATs) and tools like mimikatz, to gain access and exfiltrate data.
• Impact — Attackers accessed hundreds of millions of customer records in the Starwood guest reservation database. The data included not just names but highly sensitive content like passport numbers and payment card numbers with expiration dates. Marriott offered guests a free year of identity monitoring services. In 2024, the company agreed to pay a $52 million penalty for this incident and two other data breaches, as well as to improve their processes for handling and protecting sensitive data.

Sony’s PlayStation Network (PSN) (2011)

Sony’s PlayStation Network, one of the largest gaming and digital entertainment platforms, suffered an attack in 2011.

• Methodology — Hackers exploited vulnerabilities in the PSN infrastructure, weak server security and storage of data without proper encryption.
• Response — When Sony detected unauthorized access, it shut down the PlayStation Network to investigate the breach. Full restoration of services took several weeks.
• Impact — The breach compromised the personal data of nearly 77 million PSN accounts, including names, addresses, email addresses, birth dates and login credentials. Sony estimated the cost of the breach at $171 million. They company was required to implement new encryption protocols, firewalls and monitoring systems to strengthen network security. As a lure, it launched a “Welcome Back” program offering affected users free games, movies and a month-long PlayStation Plus subscription.

Equifax (2017)

Equifax, one of the largest credit reporting agencies in the US, suffered one of the largest breaches of sensitive data to date. In February 2020, the US government indicted members of China’s People’s Liberation Army for the incident.

• Methodology — To gain access to the Equifax corporate network, attackers exploited a vulnerability in an open-source web application framework called Apache Struts. They then compromised credentials for Equifax employees, which enabled them to access the credit monitoring databases. To avoid detection, the hackers carefully exfiltrated the data piece by piece from 51 databases.
• Response —The breach went undetected for 76 days. After it was discovered, Equifax turned down assistance from the Department of Homeland Security and instead engaged a private cybersecurity company to help with breach response. Analysis revealed that a patch was available for the Apache Struts flaw well before the breach but Equifax had not yet applied it. (Indeed, a 2015 internal audit had uncovered systemic issues with the company’s patching process, but most of them had not been addressed before the 2017 breach.) In addition, some systems lacked proper encryption and security protocols.
• Impact — The incident exposed the sensitive information of some 147.9 million US residents (nearly half the country’s population) and millions of British and Canadian citizens. Equifax incurred $1.4 billion in costs, including free credit monitoring and identity theft protection for affected individuals and cybersecurity improvements like stronger encryption, MFA and real-time threat monitoring. Equifax also faced several lawsuits and investigations from regulators and private entities. The incident prompted congressional hearings and calls for stricter data protection laws.

Notable Espionage Cyber Attacks

Google (2009)

A sophisticated attack on Google in 2009 was aimed at gathering intelligence on human rights activists and political dissidents critical of the Chinese government. It was also likely part of a broader effort to steal intellectual property and corporate secrets.

• Methodology — Attackers exploited a zero-day vulnerability in Microsoft Internet Explorer that enabled them to remotely execute malicious code called Aurora, to establish a foothold and exfiltrate data. They also used spear-phishing emails to target employees and gain access to the system.
• Response — The attack targeted Google’s infrastructure in China, but more than 20 other organizations were victims, including Adobe Systems, Yahoo, Juniper Networks and Northrop Grumman.
• Impact — This cyber espionage incident had far-reaching implications. Google announced it would no longer censor search results in China as required by Chinese law; instead, it began redirecting Chinese users to its uncensored Hong Kong site. The attack also strained US-China relations. While Google did not directly accuse the Chinese government, cybersecurity experts and US officials pointed to Chinese state-sponsored hackers as the likely culprits.

Iran’s Nuclear Program (2010)

The 2010 Stuxnet cyber attack was a groundbreaking and highly sophisticated operation that targeted Iran’s nuclear enrichment program. It used a computer worm to physically damage industrial equipment, marking a new era in cyber warfare.

• Background — By the early 2000s, Iran was enriching uranium, causing concern among Western nations that it could acquire nuclear weapons and further destabilize the region. Diplomatic efforts and economic sanctions had failed to halt Iran’s progress.
• Methodology — The cyber attack relied on Stuxnet, a sophisticated computer worm believed to be jointly developed by the US and Israel in a covert operation. . To infiltrate the industrial control systems at Iran’s uranium enrichment plants, which lacked internet connections, the worm spread through infected USB drives and exploited zero-day vulnerabilities in Windows systems. Once inside, Stuxnet altered the operational parameters of the centrifuges, causing them to spin at speeds beyond their tolerance, leading to mechanical failures. At the same time, it sent false feedback to monitoring systems, making it appear as though operations were running normally.
• Impact — Stuxnet reportedly destroyed around 1,000 centrifuges, a significant setback to Iran’s goal of gaining weapons-grade uranium. The attack escalated the global cyber arms race, with more nations investing in offensive and defensive cyber capabilities. In particular, Iran began launching cyber attacks on US financial institutions and infrastructure. The use of Stuxnet also raised debates about the legality of cyber attacks under international law.

Improving Cyber Attack Prevention and Response

The cyber attacks detailed above highlight the need for all organizations to enhance their cybersecurity measures and resilience planning, as well as for international cooperation in combatting evolving threats.

Building an Incident Response Strategy

Organizations looking to build an effective incident response plan should consider including the following strategies:

Immediate Containment and Mitigation

• Disconnect affected systems from the network to prevent the attack from spreading.
• Activate internal or external cybersecurity teams to assess and neutralize the attack.
• Use clean backups to restore data and systems if compromised.
• Prioritize critical data and infrastructure.
• Engage law enforcement agencies to investigate and trace attackers.

Communication

• Notify all employees about the breach and provide guidelines.
• If customer data is compromised, follow legal requirement and internal policies about notifying affected parties.
• Issue press releases to maintain transparency and control the narrative.

Investigation

• Investigate the nature of the attack, the vector of entry and the identity of attackers.
• Perform root-cause analysis to identify and fix vulnerabilities to prevent recurrence.

Legal and Regulatory Compliance

• Report the attack to relevant authorities, such as data protection agencies.
• If the incident was the result of negligence by a third-party vendor, consider legal action.

Strengthen Defenses

• Apply patches to update software and close vulnerabilities.
• Implement firewalls, intrusion detection systems and endpoint security tools to enhance security.
• Educate employees on recognizing phishing and other threats.

Government Response Options

In addition to directly addressing breaches using the response strategies above, governments may have additional options available, such as the following:

Diplomatic Measures

• Publicly identify the responsible party.
• Impose economic or political sanctions on entities that conduct or sponsor attacks.
• Collaborate with international partners and alliances like NATO or the UN to strengthen collective cybersecurity defenses.

Legal and Policy Actions

• Strengthen cybercrime legislation to enforce appropriate laws and prosecute attackers.
• Establish reporting requirements for companies to improve transparency.
• Foster multi-national and international cooperation between law enforcement agencies tasked with battling cyber crime

Capacity Building

• Develop frameworks for risk management and prevention.
• Collaborate with private companies to secure critical infrastructure.
• Launch awareness campaigns to educate the public on cyber hygiene.

Retaliation

Retaliation can be divided into two variants: hackbacks and counterattacks.

• In a hack back scenario, the attacked state tries to counter the cyber attack by hacking back the perpetrator. Hack backs are controversial, and most researchers do not see them as a valid option.
• The other, even more extreme variant, in which countries might consider launching physical counterattacks, is discussed in policy forums. So far, a military response has never been used cyber attacks a direct retaliation for a cyber attack.

Cybersecurity Best Practices for Businesses and Governments

To enhance resilience against cyber threats, organizations in any sector can adopt the following measures:

Threat Prevention

• Strictly enforce the principle of least privilege and limit each user’s access rights to what is necessary for their role.
• Implement intelligent MFA.
• Regularly update and patch systems.
• Perform regular risk assessments to identify vulnerabilities.
• Conduct periodic penetration testing to test the effectiveness of current defenses against simulated cyber attacks.
• Implement a Zero Trust policy for network access.
• Conduct security awareness training for all users, being sure to cover phishing, social engineering and other common attack vectors and provide an easy way to report suspicious activities. Use simulated threat scenarios, such as run mock phishing campaigns, to test employee response and awareness.

Threat Detection and Response

• Improve threat detection by deploying endpoint detection and response (EDR) and intrusion detection systems (IDS).
• Monitor activity and use advanced analytics to spot suspicious behavior.
• Subscribe to threat intelligence feeds to stay informed about new exploits.
• Partner with cybersecurity firms, law enforcement and government agencies to share threat intelligence and other resources.

Incident Recovery

• Create a comprehensive incident response plan that outlines roles, responsibilities, and steps to contain and recover from cyber incidents.
• Back up data and key systems like Active Directory regularly and test the backups thoroughly. Store all backups securely using offsite, immutable storage.

How Netwrix Can Help

Netwrix offers a suite of solutions to help organizations strengthen their defenses against cyber attacks, detect threats early and mitigate potential damage. They include:

• Netwrix Auditor provides comprehensive visibility into IT environments by auditing changes, configurations and access permissions. It enables organizations to detect suspicious activities, investigate incidents and address vulnerabilities to reduce the risk of attacks.
• Netwrix Threat Prevention delivers real-time monitoring and analytics to identify unusual behavior and potential threats within your infrastructure, enabling proactive action to mitigate risks.
• Netwrix Threat Manager empowers security teams with automated threat response capabilities, streamlining incident management and reducing the time it takes to address security incidents effectively.
• Netwrix Endpoint Protector thwarts cyber attacks at their source by securing endpoints. It monitors and controls access to sensitive data, detects suspicious activity, and prevents unauthorized changes and data exfiltration.

Conclusion: Lessons from the Biggest Cyber Attacks

History teaches that cyber threats are a persistent and growing challenge. As technology has evolved, so have attack methodologies. Cybercrime has become increasingly commercialized, with dark web platforms facilitating the sale stolen data and offering ransomware and other options as services. Nations now use cyber capabilities for espionage, sabotage and influence, with critical infrastructure now a top target with devastating real-world impacts.

Moving forward, we can expect an expansion in attack surfaces. The proliferation of Internet of Things (IoT) devices, from smart homes to industrial sensors, will create more entry points for attackers. By 2030, billions of devices will be connected, many with inadequate security. As artificial intelligence becomes embedded in critical systems, attackers will target vulnerabilities in AI models and their decision-making processes. The rollout of 5G and future network technologies will increase connectivity, exposing more networks to more cyber threats.

At the same time, threats will become even more sophisticated. Adversaries will use AI to create more advanced malware, automate attacks and mimic human behavior in phishing schemes. Quantum computers could render current encryption methods obsolete, exposing sensitive data to decryption.

The keys to mitigating risk include preparation, collaboration and innovation. The human element remains an important weak link, highlighting the need for robust training and effective access controls. Advanced technologies can play an important role in defense as well as attack; for example, AI can enable faster and more accurate threat detection and response while quantum computing will enable stronger encryption and better secure communication systems. More broadly, organizations must establish clear incident response plans, maintain reliable backups and implement robust resilience strategies.

FAQ

What is the largest cyber attack in history?

The most destructive cyber attack in history is widely considered to be the NotPetya attack of June 2017. Though the primary target was Ukraine, the malware rapidly spread globally, with estimated damage in excess of $10 billion.

What was the largest cyber attack in the US?

The largest attacks in the United States include:

• SolarWinds — In 2020, attackers inserted malicious code into SolarWinds’ Orion software updates, which were then distributed to numerous clients, including US federal agencies and Fortune 500 companies.
• Colonial Pipeline — In May 2021, Colonial Pipeline, a major US fuel distributor, suffered a ransomware attack that shut down pipeline operations, causing fuel shortages.
• Chinese cyber espionage — In 2024, Chinese hackers targeted the cellphones of US political figures, including presidential candidates and their associates. This operation was part of a broader espionage effort aimed at collecting private data and influencing political processes.

What are the most famous cyber attacks?

Cyber attacks that stand out due to their global significance, media coverage and long-lasting effects include:

• Stuxnet — This malware attack on Iran’s uranium processing plants is considered the first-known cyberweapon targeting physical infrastructure.
• WannaCry — This ransomware attack affected over 200,000 computers in 150 countries.
• NotPetya — The total damage from this destructive malware is estimated to exceed $10 billion.
• Equifax — This breach exposed the personal data of 147.9 million US residents, plus millions of British and Canadian citizens.

What was the worst cybercrime committed?

Some contenders for the worst cybercrime include:

• NotPetya (2017), which brought down major companies around the globe
• WannaCry (2017), which encrypted Windows systems globally for ransom
• Equifax (2017), which exposed the personal data of more than 148 million people
• Yahoo (2013), in which three billion accounts were compromised

What happens in a major cyber attack?

Cyber attacks generally involve multiple phases. First, attackers gather information about the target’s systems, networks and vulnerabilities. To gain an initial foothold, they often use methods like phishing, malware, vulnerability exploits or stolen credentials. Once inside, they escalate their privileges and move laterally to additional systems. Finally, they complete their mission by disrupting operations or stealing or encrypting data, and delete logs to cover their tracks.

When an attack is detected, organizations respond by isolating affected systems; analyzing how the breach occurred and identifying attackers; restoring systems from backups and patching vulnerabilities; and informing affected parties, stakeholders and law enforcement bodies about the breach. Consequences can include recovery costs, reputation damage and lost business, fines, lawsuits, and stricter oversight.

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Dirk Schrader

Dirk Schrader is a Resident CISO (EMEA) and VP of Security Research at Netwrix. A 25-year veteran in IT security with certifications as CISSP (ISC²) and CISM (ISACA), he works to advance cyber resilience as a modern approach to tackling cyber threats. Dirk has worked on cybersecurity projects around the globe, starting in technical and support roles at the beginning of his career and then moving into sales, marketing and product management positions at both large multinational corporations and small startups. He has published numerous articles about the need to address change and vulnerability management to achieve cyber resilience.