15 Of The Biggest Data Breaches In History

Last updated by Kelly Rethmeyer on June 26, 2019

Data is rapidly becoming one of the most valuable assets in the modern world. The digital giants that monopolize data are arguably the most powerful companies in the world, prompting ongoing conversations about anti-trust legislation and digital privacy.

Despite the overwhelming value controlled by these entities, as we'll see, even companies such as Facebook are vulnerable to the byproduct of the rapid move to digitization -- the data breach epidemic.

What defines a data breach? A security incident in which personal information is publicly exposed or accessed without authorization. Although companies such as Yahoo and Facebook have gotten widespread attention for the impact of these incidents of cyber risk exposure, data breaches can affect businesses of all sizes in a variety of ways.

They are difficult to identify, are costly to address, and cause reputational damage that some businesses never recover from. However, given the value of data and the inevitability of cyber risk, the best that companies can do to mitigate the effects of a breach is to implement a thorough risk management practice for the detection, containment and communication in the wake of a data breach. According to IBM, companies that contained a breach in less than 30 days saved more than $1 million compared to those that took more than 30 days.

Biggest Data Breaches by People Impacted

Each of these data breaches had an impact on millions of people, and provide different examples of how a company can be compromised or leave data exposed.

  1. Yahoo - 3 billion
  2. Aadhaar - 1.1 billion
  3. Yahoo - 500 million
  4. Marriott/Starwood - 500 million
  5. Adult Friend Finder - 412.2 million
  6. MySpace - 360 million
  7. Exactis - 340 million
  8. Twitter - 330 million
  9. LinkedIn - 165 million
  10. MyFitnessPal - 150 million
  11. Equifax - 148 million
  12. eBay - 145 million
  13. Quora - 100 million
  14. MyHeritage - 92 million
  15. Facebook - 87 million

1. Yahoo

Date: October 2017

Impact: 3 billion accounts

Yahoo disclosed that a breach in August 2013 by a group of hackers had compromised 1 billion accounts. In this instance, security questions and answers were also compromised, increasing the risk of identity theft. The breach was first reported by Yahoo on December 14, 2016, and forced all affected users to change passwords, and to reenter any unencrypted security questions and answers to make them encrypted in the future.

However, by October of 2017, Yahoo changed the estimate to 3 billion user accounts. An investigation revealed that users' passwords in clear text, payment card data and bank information were not stolen. Nonetheless, this remains one of the largest data breaches of this type in history.

2. Aadhaar

Date: March 2018

Impact: 1.1 billion people

In March of 2018, it became public that the personal information of more than a billion Indian citizens stored in the world’s largest biometric database could be bought online.

This massive data breach was the result of a data leak on a system run by a state-owned utility company. The breach allowed access to private information of Aadhaar holders, exposing their names, their unique 12-digit identity numbers, and their bank details.

The type of information exposed included the photographs, thumbprints, retina scans and other identifying details of nearly every Indian citizen.

3. Yahoo

Date: 2014

Impact: 500 million accounts

Yahoo believed that a "state-sponsored actor" was behind this initial cyberattack in 2014. The stolen data included personal information such as names, email addresses, phone numbers, hashed passwords, birth dates, and security questions and answers, some of which were unencrypted. Yahoo had become aware of this breach back in 2014, taking a few initial remedial actions but failing to investigate further. It was only about two years later that Yahoo publicly disclosed the breach after a stolen database from the company allegedly went up for sale on the black market.

4. Marriott/Starwood

Date: November 2018

Impact: 500 million guests

In November 2018, Marriott International announced that hackers had stolen data about approximately 500 million Starwood hotel customers. The attackers had gained unauthorized access to the Starwood system back in 2014 and remained in the system after Marriott acquired Starwood in 2016. However, the discovery was not made until 2018.

The information that was exposed included names, contact information, passport number, Starwood Preferred Guest numbers, travel information, and other personal information. Marriott believes that financial information such as credit and debit card numbers, and expiration dates of more than 100 million customers were stolen, although the company is uncertain whether the attackers were able to decrypt the credit card numbers.

According to the New York Times, the breach was eventually attributed to a Chinese intelligence group, The Ministry of State Security, seeking to gather data on US citizens. If true, this would be the largest known breach of personal data conducted by a nation-state.

5. Adult Friend Finder

Date: October 2016

Impact: 412.2 million accounts

In October 2016, hackers collected 20 years of data on six databases that included names, email addresses and passwords for The FriendFinder Network. The FriendFinder Network includes websites like Adult Friend Finder, Penthouse.com, Cams.com, iCams.com and Stripshow.com.

Most of the passwords were protected only by the weak SHA-1 hashing algorithm, which meant that 99% of them had been cracked by the time LeakedSource.com published its analysis of the entire data set on November 14.

6. MySpace

Date: June 2013

Impact: 360 million accounts

In June 2013 around 360 million accounts were compromised by a Russian hacker, but the incident was not disclosed publicly 2016. The information that was leaked included account information such as the owner’s listed name, username, and birthdate. Between 2013 and 2016, anyone who gained access to this breached information could have taken over any Myspace account. The former social media network giant has since invalidated all passwords belonging to accounts that were set up prior to 2013.

7. Exactis

Date: June 2018

Impact: 340 million people

In June of 2018, Florida-based marketing and data aggregation firm Exactis exposed a database containing nearly 340 million records on a publicly accessible server. The breach exposed highly personal information such as people's phone numbers, home and email addresses, interests and the number, age and gender of their children. This data exposure was discovered by security expert Vinny Troia, who indicated that the breach included data on hundreds of millions of US adults and millions of businesses.

8. Twitter

Date: May 2018

Impact: 330 million users

In May of 2018, social media giant Twitter notified users of a glitch that stored passwords unmasked in an internal log, making all user passwords accessible to the internal network. Twitter told its 330 million users to change their passwords but the company said it fixed the bug and that there was no indication of a breach or misuse, but encouraged the password update as a precaution. Twitter did not disclose how many users were impacted but indicated that the number of users was significant and that they were exposed for several months.

9. LinkedIn

Date: June 2012

Impact: 165 million users

In June 2012, Linkedin disclosed a data breach had occurred, but password-reset notifications at the time indicated that only 6.5 million user accounts had been affected. LinkedIn never confirmed the actual number, and in 2016, we learned why: a whopping 165 million user accounts had been compromised, including 117 million passwords that had been hashed but not "salted" with random data to make them harder to reverse.

That revelation prompted other services to comb their LinkedIn data and force their own users to change any passwords that matched (kudos to Netflix for taking the lead on this one.) Left unanswered is why LinkedIn did not further investigate the original breach, or to inform more than 100 million affected users, in the intervening four years.

10. MyFitnessPal

Date: February 2018

Impact: 150 million users

In February 2018, the diet and exercise app MyFitnessPal (owned by Under Armour) suffered a data breach, exposing 144 million unique email addresses, IP addresses and login credentials such as usernames and passwords stored as SHA-1 and bcrypt hashes (the former for earlier accounts, the latter for newer accounts). In 2019, this sensitive data appeared listed for sale on a dark web marketplace and began circulating more broadly, so it was identified and provided to data security website Have I Been Pwned.

11. Equifax

Date: September 2017

Impact: 148 million people

In September 2017, Equifax, one of the three largest consumer credit reporting agencies in the United States, announced that its systems had been breached and the sensitive personal data of 148 million Americans had been compromised. The data compromised included names, home addresses, phone numbers, dates of birth, social security numbers, and driver’s license numbers. The credit card information of approximately 209,000 consumers was also exposed through this data breach. The sensitivity of the information processed by Equifax makes this breach unprecedented, and one of the largest data breaches to date.

12. eBay

Date: February/March 2014

Impact: 145 million users

Between February and March 2014, eBay was the victim of a breach of encrypted passwords, which resulted in asking all of its 145 million users to reset their password. Attackers used a small set of employee credentials to access this trove of user data. The stolen information included encrypted passwords and other personal information, including names, e-mail addresses, physical addresses, phone numbers and dates of birth. The breach was disclosed in May 2014, after a month-long investigation by eBay.

13. Quora

Date: December 2018

Impact: 100 million users

Quora, a popular site for Q&A suffered a data breach in 2018 exposed the personal data of up to 100 million users.

The types of leaked data included personal information such as names, email addresses, encrypted passwords, user accounts linked to Quora and public questions and answers posted by users. There was no evidence discovered that anonymously posted questions and answers were affected by the breach.

14. MyHeritage

Date: June 2018

Impact: 92 million users

MyHeritage, a genealogical service website was compromised, affecting more than 92 million user accounts. The breach occurred in October 2017, but wasn't disclosed until June 2018. A security researcher discovered a file on a private server containing email addresses and encrypted passwords. The security team at MyHeritage confirmed that the content of the file affected the 92 million users, but found no evidence that the data was ever used by the attackers. MyHeritage earned praise for promptly investigating and disclosing details of the breach to the public.

15. Facebook

Date: early 2018 (this is when a Cambridge Analytica whistleblower disclosed the story)

Impact: 87 million users

Though a slightly different type of data breach as the information was not stolen from Facebook, the incident that affected 87 million Facebook accounts represented the use of personal information for purposes that the affected users did not appreciate. Cambridge Analytica was a data analytics company that was commissioned by political stakeholders including officials in the Trump election and pro-Brexit campaigns. Cambridge Analytica acquired data from Aleksandr Kogan, a data scientist at Cambridge University, who harvested it using an app called "This Is Your Digital Life". One of the most controversial elements of this breach was that users did not appreciate or consent to the political usage of data from a seemingly-innocuous lifestyle app.

UpGuard's researchers also discovered and disclosed a related breach by AggregateIQ, a Canadian company with close ties to Cambridge Analytica. Details about these discoveries can be found in our Aggregate IQ breach series (part 1, part 2, part 3 and part 4).

 

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