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.
Rapid human innovation will only magnify this modern currency, and withoutdata leak detection solutions business will continue to fall victim to cyber attacks.
In this list, updated for 2021, we list some of the most devastating data breach incidents ranked by their level of impact.
As you’ll see, even prestigious companies like Facebook, Linkedin and Twitter are vulnerable to the rising trend of data breaches.
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 an extraordinary number of records exposed.
1. CAM4 data breach
Date: March 2020
Impact: 10.88 billion records.
Adult video streaming website CAM4 has had its Elasticsearch server breached exposing over 10 billion records.
The breached records included the following sensitive information:
- Full names
- Email addresses
- Sexual orientation
- Chat transcripts
- Email correspondence transcripts
- Password hashes
- IP addresses
- Payment logs
Many of the exposed email addresses are linked to cloud storage services. If hackers were to launch successful phishing attacks on these users, they could gain deeper access to personal photos and business information.
Due to the licentious connection of the breached database, compromised users could fall victim to blackmail and defamation attempts for many years to come.
2. Yahoo data breach 2017
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 while in negotiations to sell itself to Verizon, 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.
3. Aadhaar data breach
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.
4. First American Financial Corp. data breach
Date: May 2019
Impact: 885 million users
In May 2019, First American Financial Corporation reportedly leaked 885 million users' sensitive records that date back more than 16 years, including bank account records, social security numbers, wire transactions, and other mortgage paperwork.
5. Verifications.io data breach
Date: February 2019
Impact: 763 million users
In February 2019, email address validation service verifications.io exposed 763 million unique email addresses in a MongoDB instance that was left publicly facing with no password. Many records also included names, phone numbers, IP addresses, dates of birth and genders.
6. Facebook data breach 2019
Date: April 2019
Impact: 540 million users
In April 2019, the UpGuard Cyber Risk team revealed two third-party Facebook app datasets had been exposed to the public Internet. One, originating from the Mexico-based media company Cultura Colectiva, weighs in at 146 gigabytes and contains over 540 million records detailing comments, likes, reactions, account names, FB IDs and more. This same type of collection, in similarly concentrated form, has been cause for concern in the recent past, given the potential uses of such data. Read more about this Facebook data breach here.
7. Yahoo data breach 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.
8. Marriott/Starwood data breach
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.
9. Adult Friend Finder data breach
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.
10. MySpace data breach
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.
11. Exactis data breach
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.
12. Twitter data breach 2018
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.
13. NetEase data breach
Date: October 2015
Impact: 234 million users
In October 2015, NetEase (located at 163.com) was reported to suffered from a data breach that impacted hundreds of millions of subscribers. While there is evidence to say that the data is legitimate (many users confirmed their passwords where in the data), it is difficult to verify emphatically.
The breach contained email addresses and plain text passwords.
14. LinkedIn data breach
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.
15. Dubsmash data breach
Date: December 2018
Impact: 162 million users
In December 2018, Dubmash suffered a data breach that exposed 162 million unique email addresses, usernames and DBKDF2 password hashes. In 2019, this data appeared for sales on the dark web and was circulated more broadly.
16. Adobe data breach
Date: October 2013
Impact: 152 million
In October 2013, 153 million Adobe accounts were breached. The data breach contained an internal ID, username, email, encrypted password and password hint in plain text. The encryption was weak and many were quickly resolved back to plain text, the password hints added to the damage making it easy to guess the passwords of many users.
17. MyFitnessPal data breach
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.
18. Equifax data breach
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.
19. eBay data breach
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.
20. Canva data breach
Date: May 2019
Impact: 137 million users
In May 2019, online graphic design tool Canva suffered a data breach that impacted 137 million users. The exposed data included email addresses, names, usernames, cities and passwords stored as bcrypt hashes.
The suspected culprit(s) — Gnosticplayers — contacted ZDNet to boast about the incident, saying that Canva had detected their attack and remediate the issue that caused the data breach. The attacker also claimed to have gained OAuth login tokens for users who signed in via Google.
Canva confirmed the incident, notified users, and prompted them to change passwords and reset OAuth tokens.
21. Heartland Payment Systems data breach
Date: March 2008
Impact: 134 million credit cards exposed
At the time of the breach, Heartland was processing north of 100 million credit card transactions per month for 175,000 merchants. The breach was discovered by Visa and MasterCard in January 2009 when Visa and MasterCard notified Heartland of suspicious transactions. The attackers exploited a known vulnerability to perform a SQL injection attack.
The company paid an estimated $145 million in compensation for fraudulent payments.
22. Apollo data breach
Date: July 2018
Impact: 126 million users
In July 2018, Apollo left a database containing billions of data points publicly exposed. A subset of the data was sent to Have I Been Pwned which had 126 million unique email addresses. The full dataset included personally identifiable information (PII) like names, email addresses, place of employment, roles held and location.
23. Badoo data breach
Date: July 2013
Impact: 112 million users
In June 2013, a data breach allegedly originating from social website Badoo was found to be circulated. The breach contained 112 million unique email addresses and PII like names, birthdates and passwords stored as MD5 hashes.
24. Capital One data breach
Date: July 2013
Impact: 106 million credit card numbers
In July 2013, Capital One identified a security breach of its customer records that exposed the personal information of its customers, including credit card data, social security numbers, and bank account numbers.
25. Evite data breach
Date: August 2013
Impact: 101 million users
In April 2019, Evite, a social planning and invitation site identified a data breach from 2013. The exposed data included 101 million unique email addresses, as well as phone numbers, names, physical addresses, dates of birth, genders and passwords stored in plain text.
26. Quora data breach
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.
27. VK data breach
Date: January 2012
Impact: 93 million users
Russian social media site VK was hacked and exposed 93 million names, phone numbers, email addresses and plain text passwords.
28. MyHeritage data breach
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.
29. Youku data breach
Date: December 2016
Impact: 92 million users
Youku a Chinese video service exposed 92 million unique user accounts and MD5 password hashes.
30. Rambler data breach
Date: March 2014
Impact: 91 million users
A dump of 91 million accounts from Rambler ("Russian Yahoo") was traded online containing usernames (that form part of a Rambler email) and plain text passwords.
31. Facebook data breach 2018
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).
32. Dailymotion data breach
Date: October 2016
Impact: 85 million users
In October 2016, Dailymotion a video sharing platform exposed more than 85 million user accounts including emails, usernames and bcrypt hashes of passwords.
33. Anthem data breach
Date: February 2015
Impact: Theft of up to 78.8 million current and former customers
In February 2015, a single user at an Anthem subsidiary clicked on a phishing email which gave attackers access to names, addresses, dates of birth, and employment histories of current and former customers.
34. Dropbox data breach
Impact: 69 million users
In mid 2012, Dropbox suffered a data breach which exposed 68 million records that contained email addresses and salted hashes of passwords (half SHA1, half bcrypt).
35. tumblr data breach
Date: February 2013
Impact: 66 million users
In February 2013, tumblr suffered a data breach that exposed 65 million accounts. The breach included email addresses and salted SHA1 password hashes.
36. Uber data breach
Date: Late 2016
Impact: Personal information of 57 million Uber users and 600,000 drivers exposed.
In late 2016, Uber learned that two hackers were able to access the names, email addresses, and mobile phone numbers of 57 million users of the Uber app. They also got the driver's license numbers of 600,000 Uber drivers. In addition, the hackers were able to access Uber's GitHub account, where they found Uber's Amazon Web Services credentials.
37. Home Depot data breach
Date: September 2014
Impact: Exposure of the credit card information of 56 million customers
Home Depot announced that its POS systems had been infected with a custom-built malware, which posed as anti-virus software.
38. TJX Companies inc. data breach
Date: Jul 2005
Impact: 45.6 million card numbers
TJX, the owner of a number of retail brands, had one of its payment systems breached exposing over 45 million credit and debit card numbers. The data was garnished over several waves of breaches
The breaches occurred over several occasions ranging from July 2005 to January 2007.
TJX claimed that the names and addresses associated with each stolen card number were not exposed in the breach.
39. Ashley Madison data breach
Date: July 2015
Impact: 32 million users.
Hacking group identified as Impact Team compromised 35 million user records from the cheating website Ashley Madison.
The hackers demanded that parent company Avid Life Media shut down Ashley Madison and sister website Established Men within 30 days to avoid the publication of compromised records.
Avid Life Media failed to comply which resulted in wave after wave of categorised data dumps in Pastebin. The list of exposed users included members of the military and government.
The following records were included in the accessed data:
- Seven years worth of credit card payment history
- Full names
- Residential Addresses
- Email addresses
- Descriptions of what members were seeking
Impact Team claimed the breach was easy to achieve with little to no security to bypass.
40. MGM grand data breach
Date: Feb 2020
Impact: 10.6 million customers.
Hackers gained access to over 10 million guest records from MGM Grand. The records exposed the contact information of former hotel guests including Justin Bieber, Twitter CEO Jack Dorsey, and government officials.
MGM Grand assures that no financial or password data was exposed in the breach.
41. Easyjet data breach
Date: May 2020
Impact: 9 million customers.
A highly sophisticated cyber attack breached Jetstar’s security barriers compromising the data of 9 million customers.
Data accessed in the breach included travel details email addresses as well as the complete credit card details of 2,208 customers.
Because customer credit card information was leaked, this cyber attack exposes Easyjet’s breach of the General Data Protection Regulation, which could result in a fine of up to 4% of its global annual turnover.
42. Marriott data breach
Date: March 2020
Impact: 5.2 million guests
Marriott has once again fallen victim to yet another guest record breach. On March 31, the company announced that up to 5.2 million records were compromised. Some of the records accessed include
While the exact list of records breached is yet to be conformed, it’s believed that the following guest records were compromised:
- Email address
- Mail addresses
- Phone numbers
- Company names
- Birth dates
- Accommodation preferences
- Language preferences
- Linked airline loyalty programs and numbers
Marriott stated in its press release that the breach is not believed to have exposed pin numbers, payment card information, national IDs, drivers license numbers or loyalty card passwords.
By multiplying its internal login authentications and continuously scanning for data breaches, Marriott could mitigate, or completely prevent future cyber attacks.
43. Zoom data breach
Date: April 2020
Impact: 500,000 users.
When Zoom sign ups were nearing their pandemic peak in April of 2020, hackers breached 500,000 accounts and either sold or freely published them on the dark web.
Hackers initially canvassed dark web databases of previously compromised login credentials dating back to 2013. Because passwords are usually recycled, this gave them instant access to a swathe of active Zoom accounts.
A series of credential stuffing attacks was then launched to compromise the remaining accounts.
Recipients of compromised Zoom accounts were able to log into live streaming meetings.
44. Deep Root Analytics data breach
Date: Jun 2017
Impact: 200 million U.S voters
The records of 200 million voters was accessed from Deep Root Analytics, a firm working on behalf of the Republican National Committee (RNC).
The data consisted of 1.1 terabytes of voter Personal Identifiable Information (PII) including names, addresses and birthdates.
The accessed data also contained comprehensive voter analysis based on Reddit post activity which could be used to predict how somebody would vote on a particular issue.
The breached database was discovered by Upguard director of cyber risk research Chris Vickery.
45. Court Ventures data breach
Date: Oct 2013
Impact: 200 million personal records
Court Ventures, a subsidiary of credit card monitoring firm Experian, was breached exposing 200 million personal records.
The hacker was running a business selling Personal Identifiable Information and was selling the credit card numbers and social security numbers he had accessed in the breach.
Penetration was achieved by the hacker posing as a private investigator from Singapore and convincing staff to relinquish access to the internal database.
Date: Fev 2020
Impact: 370,000 customers
Slickwraps, a manufacturer of vinyl skins for phones and tablets, suffered a breach impacting 370,000 of its customers.
This breach could have been avoided if Slickwraps listened to the warnings of a white hat hacker highlighting the company’s terrible cybersecurity. After being ignored, the hacker echoed his concerts in a medium post.
Slickwraps still ignored the warnings.
Before the medium post was deleted, a second hacker read it and decided to also try to convince Slickwraps but with a slightly more impactful approach.
The second hacker actually breached Slickwraps’s abysmal defences and announced their cybersecurity complacency in an email to over 370,000 of its customers.
47. Magellan Health ransomware attack
Date: Apr 2020
Impact: 365,000 patients
Magellan Health, a Fortune 500 company has been the victim of a sophisticated ransomware attack where over 365,000 patient records were breached.
Employee login information was first accessed from malware that was installed internally. Then, by posing as a Magellan client in a phishing attack, the hackers gained access to a single corporate server and implemented their ransomware.
Included in the breached data was patient social security numbers, W-2 information and employee ID numbers.
48. Nintendo data breach
Date: April 2020
Impact: 300,000 accounts.
300,000 Nintendo accounts were compromised and used to make unsolicited digital purchases. The number affected accounts was almost doubled from the originally stated 140,000 upon further investigation.
The following information was exposed:
- Account passwords
- Account owner name
- Email addresses
- Country of residence
While it isn’t clear how hackers gained access to accounts, it’s speculated that weak passwords are to blame. To prevent further breaches, Nintendo posted a tweet asking members to enable 2-step authentication.
49. Mailfire data breach
Date: September 2020
Impact: 100,000 users.
Mailfire, an email marketing software used by adult dating sites and ecommerce websites, had its database breached exposing personal user records from over 70 websites.
The breach occurred through Mailfire’s unsecured Elasticsearch server. Onced breached, the hacker had access to over 320 million records from notifications being pushed out to Mailfire clients.
The records exposed included private conversations between adult dating site members as well as the following Personally Identifiable Information:
- Location of message senders
- IP addresses
- Member profile pictures
- Member bio descriptions
Besides the personal information of website members, this data breach also exposed many scam dating websites with fabricated female profiles..
50. Antheus Tecnologia
Date: March 2020
Impact: 76,000 fingerprints
Antheus Tecnologia, a Brazilian biometrics company specializing in the development of Fingerprint Identification Systems (AFIS), suffered a breach to its server which could potentially expose 76,000 unique fingerprint records.
The data accessed consists of 2.3 millions data points which could be reverse engineered to recreate each original fingerprint.
Besides finger print data points, 81.5 million records were accessed, consisting of email addresses, employee telephone numbers and administrator login information.
Date: March 2020
Impact: 18,000 customers
In March 2020, nation-state hackers believed to be from Russian, compromised a DLL file linked to software update for the Orion platform by SolarWinds. The supply chain attack impacted up to 18,000 SolarWinds customers including six U.S Government departments.
The attack wasn’t discovered until December 2020.
The highly sophisticated hackers are believed to also be responsible for the FireEye cyberattack resulting in the theft of its Red Team Assessment tools - a set of tools developed by FireEye to discover cyberattack vulnerabilities within any organizations.
Given that FireEye’s clientbase includes government entities, it is further speculated that these Red Team Assessment tools made the U.S. Government data breach possible - an attack labeled by cyber security experts as the biggest breach in the nation’s security history.
52. Twitter phone spear phishing attack 2020
Date: July 2020
Impact: 130 users.
A successful spear phishing attack on July 15th resulted in a selection of high profile accounts publishing a bitcoin scam. 130 accounts were targeted including those of Barack Obama, Elon Musk, Joe Biden and Bill Gates
The following message was tweeted:
“I’m giving back to the community. All bitcoin sent to the address below will be sent back doubled! If you send $1000, I will send back $2000. Only doing this for 30 minutes,”
Of the 130 targeted accounts, tweets were published from 45, DM messages were accessed from 36 and Twitter data was downloaded from 7.
The breach was achieved by hackers calling Twitter employees posing as colleagues and asking for credentials to internal systems.
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