The hacking of WhatsApp - in which spyware was sneaked into phones, compromising personal data - is one of the most spectacular of a series of such attacks in recent years.
The instant messaging service used by 1.5 billion people worldwide said Tuesday a security breach had allowed sophisticated attackers to install the malicious software into phones via its app.
Here are some previous cases of a similar kind.
Yahoo, billions hacked
In what is considered the biggest cyber-attack in history, a 2013 hack affected all three billion accounts at Yahoo.
Another attack on Yahoo, blamed on Russian hackers, affected some 500 million accounts in 2014, with stolen data including usernames, email addresses and birthdates.
It was only revealed in September 2016 and resulted in fine of $35 million (roughly Rs. 245 crores) in 2018 for its then-financial arm, Altaba.
Taking aim at Target
The US retail giant was hit by a computer attack in 2013 that affected 110 million clients.
Seventy million might have lost personal data including names, addresses, phone numbers and e-mail accounts, while 40 million bank accounts and credit cards were also put at risk.
In 2014 online data protection firm Hold Security claimed that Russian hackers had accessed 1.2 billion passwords linked to 420,000 internet sites around the world, from corporate giants to individual accounts.
Hold Security pointed to a group of hackers called "CyberVor", which it said had potentially gained access to 500 million e-mail accounts.
South Korea panic
In 2014 the personal data of at least 20 million bank and credit card users in South Korea was leaked in one of the country's biggest ever breaches.
An employee from personal credit ratings firm Korea Credit Bureau (KCB) had stolen the data from customers of three credit card firms and sold it to phone marketing companies.
In 2015 hackers calling themselves The Impact Team published nearly 30 gigabytes of files including the names and sexual orientation of people who had signed up with Ashley Madison, a website facilitating extra-marital affairs.
The company's boss stepped down as several suicides in the United States and Canada were linked to the revelations.
Ashley Madison had earlier offered to delete users' personal data for a modest fee but did not.
Uber off the road
The ride-sharing giant was vilified after the hacking in 2016 of data on 57 million of its riders and drivers, unveiled only in November 2017.
It was also criticised for paying the hackers $100,000 (roughly Rs. 70 lakhs) to destroy their booty.
Uber was fined $148 million (roughly Rs. 1,000 crores) for covering up the fraud, and was also prosecuted in The Netherlands and Britain.
Equifax loses credit
A breach by major American credit agency Equifax in 2017 might have affected more than 147 million US clients, plus others from Canada and Britain.
The company was sued for having identified but not corrected the breach, having insufficient security systems and delaying reporting the problem.
Facebook under fire
In 2018 hackers exploited a trio of software flaws to access the personal data of 29 million Facebook users, getting hold of names, phone numbers and email addresses.
The breach sparked renewed criticisms of Facebook after it acknowledged that tens of millions of users had their personal data hijacked by Cambridge Analytica, a political firm working for Donald Trump in 2016.
Intrusion at Marriott
Global hotel giant Marriott International said in November 2018 up to 383 million guests may have been victims of a hack, involving five million passport numbers and less than 2,000 credit card numbers.
US Secretary of State Mike Pompeo blamed China.
We discussed what WhatsApp absolutely needs to do in 2019, on Orbital, our weekly technology podcast, which you can subscribe to via Apple Podcasts or RSS, download the episode, or just hit the play button below.