The Top 5 Most Dangerous Cyber Attacks of All Time


The Top 5 Most Dangerous Cyber Attacks of All Time

The frequency of cyber attacks is increasing and there is no indication of a decline in their occurrence. Indeed, it is widely acknowledged by numerous experts that our current understanding of cybercrime is merely scratching the surface of a much larger and complex phenomenon.  With the ongoing transition of enterprises towards digital platforms, their susceptibility to cyberattacks is progressively heightened. This blog post aims to examine the five most perilous cyberattacks recorded in history.  The aforementioned attacks have resulted in significant financial losses amounting to billions of dollars and have had a profound impact on a vast number of individuals, numbering in the millions.

1. The WannaCry Ransomware Attack (2017)

We begin our list with the WannaCry ransomware attack. In May 2017, enterprises and organizations across the globe were targeted by this attack. Data on the computers of its victims was encrypted by the WannaCry ransomware, which demanded a ransom payment to decrypt the data. Over 200,000 computers across 150 countries were impacted by this assault.

The peril posed by the WannaCry ransomware attack was heightened by the fact that it exploited a previously unknown Microsoft Windows vulnerability. As a consequence, numerous organizations lacked readiness for this form of assault. Additionally, the WannaCry ransomware spread rapidly due to a capability that enabled it to infect multiple computers.

Although the WannaCry ransomware attack caused significant damage, it was far from catastrophic. A disabling switch, fortunately, discovered by a security researcher, halted the propagation of the malware. Despite this, the harm that had already been inflicted continued.

2. The NotPetya Virus (2017)

Assuming precedence in our list is the NotPetya virus. This virus, which was initially identified in June 2017 and rapidly propagated globally, instigated a deluge of cyber assaults that inflicted damage amounting to billions of dollars. The NotPetya virus prevented victims from accessing their data by encrypting their hard drives. A significant number of enterprises were compelled to cease operations due to the impact of this pathogen.

NotPetya was an especially deadly virus due to the fact that it masqueraded as ransomware. As a result, individuals were duped into obtaining and installing the malware, which facilitated its rapid spread. In contrast to conventional ransomware, the NotPetya malware failed to offer victims a method to retrieve their compromised data. This significantly increased its destructiveness.

Although organizations of every scale were impacted by the NotPetya virus, Ukrainian establishments were struck especially hard. This is due to the fact that the initial vector of transmission for the virus was a widely used accounting software application in Ukraine. It subsequently spread rapidly to other nations.

Although billions of dollars were damaged by the NotPetya virus, its true purpose remains unknown. Certain authorities contend that its inception was an attempt at information warfare, whereas others assert that it was merely an unintended hoax. Regardless, it is indisputable that the NotPetya malware constituted one of the most catastrophic cyber assaults ever recorded.

3. The Equifax Data Breach (2017)

The third cyber attack on our list is the Equifax data breach, an appropriately titled breach. The intrusion compromised the private information of 147.9 million Americans, 15.2 million British citizens, and approximately 19,000 Canadian citizens, making it one of the largest identity theft-related cybercrimes. Sensitive data, including addresses, dates of birth, and social security numbers, was compromised by the hackers. The aforementioned intrusion significantly affected both the credit reporting agency and its clientele.

The Equifax data breach posed a distinctive risk due to the compromise of highly sensitive information. This information is susceptible to identity theft and additional criminal activities. A significant number of individuals were also impacted, making this one of the most extensive data intrusions in recorded history.

Following the Equifax data exposure, the organization faced widespread censure regarding its inadequate security protocols. The intruders successfully infiltrated Equifax’s systems through the exploitation of a publicly acknowledged susceptibility that had not been updated. This demonstrated that Equifax had neglected to implement adequate security measures to safeguard the data of its customers. This further demonstrates the value of routine penetration testing, which identifies and patches newly discovered vulnerabilities before they become active targets of an attack.

The Equifax intrusion serves as a poignant illustration of the criticality of cybersecurity measures. Organizations that fail to safeguard the information of their consumers will be subject to severe repercussions.

4. The Mirai Botnet Attack (2016)

Our list concludes with the Mirai botnet attack as the fourth item. This attack, which occurred in October 2016, specifically targeted cameras and routers that were connected to the internet. Utilizing the Mirai botnet, denial-of-service attacks were launched against organizations and websites. Countless individuals were impacted and billions of dollars were damaged as a result of these assaults.

Top 5 Most Dangerous Cyber Attacks

The Mirai botnet cyber-attack posed a heightened threat due to its execution methodology. A network of compromised devices was utilized by the attackers to initiate their assaults. This meant that any location in the world could launch an attack. Additionally, it was possible to infect a large number of devices with the Mirai botnet, which contributed to its immense strength.

Although formidable in nature, the Mirai botnet was ultimately dismantled. An arrest was made and the perpetrators were subsequently sentenced to prison. However, their actions continue to cause lasting damage. The Mirai botnet attack demonstrated the susceptibility of devices connected to the internet and the devastation that can result from a cyberattack.

5. The Yahoo Data Breach (2014)

The last attack on our list pertains to the Yahoo data leak. The aforementioned extensive data breach transpired in the year 2014, resulting in the compromise of personal information belonging to a staggering number exceeding three billion users of the Yahoo platform. The unauthorized individuals successfully obtained entry to confidential data, including personal identifying information such as individuals’ names, dates of birth, residential addresses, and login credentials. The aforementioned breach had a significant influence on the prominent online corporation and its clientele.

Top 5 Most Dangerous Cyber Attacks

The cyber attack on Yahoo represents the most significant data leak in recorded history. The magnitude of the breach is remarkable. Furthermore, the compromised sensitive information has the potential to be exploited for the purpose of engaging in identity theft and several other criminal activities. The cyber-attack was specifically aimed at compromising a total of 500 million accounts, successfully acquiring sensitive information such as account names, email addresses, telephone numbers, date of birth, hashed passwords, as well as a combination of encrypted and unencrypted security questions.

According to the FBI’s disclosure in 2016, the hackers successfully into Yahoo’s system as a result of a single click on a spear phishing email. In the contemporary era, it is imperative for firms of all scales to accord significant importance to staff training pertaining to phishing.


The attacks mentioned above have resulted in significant financial losses amounting to billions of dollars and have had a profound impact on a vast number of individuals, numbering in the millions.  The matter of cybersecurity holds significant importance and necessitates organizations to approach it with utmost seriousness.  Alternatively, individuals will encounter significant repercussions, as seen in the aforementioned instances.

The use of routine Penetration Testing can effectively identify and bring attention to emerging vulnerabilities, hence facilitating their prompt resolution, thereby mitigating the risk of falling victim to potential attacks.  The frequency of data breaches and sophisticated attacks is increasing, and their potential impact is expected to escalate over time.

In a nutshell, News4Hackers can certainly assist you in learning more everything about Cyberattacks and the methods to prevent them through its dedicated sister vertical, Craw Security, which is the leading cybersecurity training institute in India.

About The Author:

Yogesh Naager is a content marketer who specializes in the cybersecurity and B2B space.  Besides writing for the News4Hackers blog, he’s also written for brands including CollegeDunia, Utsav Fashion, and NASSCOM.  Naager entered the field of content in an unusual way. He began his career as an insurance sales executive, where he developed an interest in simplifying difficult concepts.  He also combines this interest with a love of narrative, which makes him a good writer in the cybersecurity field.  In the bottom line, he frequently writes for Craw Security.



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