The firm behind the Pegasus spyware has been ordered to pay WhatsApp $167m (£125m) for hacking 1,400 people in 2019.
Pegasus is malicious software which can be installed remotely on mobile phones to access, among other things, people’s microphones and cameras.
NSO Group, which sells the tech, has been accused of enabling authoritarian regimes to monitor journalists, activists and even political figures.
WhatsApp owner Meta said it marked the “first victory against the development and use of illegal spyware”.
NSO said it would “carefully examine the verdict’s details and pursue appropriate legal remedies, including further proceedings and an appeal“.
It is the first time a developer of spyware has been held responsible for exploiting the weaknesses in smartphone platforms.
NSO Group says the tech is only meant to be for use against serious criminals and terrorists. But there are accusations the tech has been used by some countries to target anyone they deem a national security threat.
Pegasus became a scandal in 2021 when a list of 50,000 phone numbers of suspected victims of hacking was leaked to major media outlets.
From this list, global media identified the phone numbers of politicians and heads of state, business executives, activists, and several Arab royal family members, as well as more than 180 journalists.
It is suspected that Pegasus spyware infected devices belonging to Downing Street and Foreign Office officials, according to Canadian investigative group The Citizen Lab.
Other prominent figures believed to have been hacked include French President Emmanuel Macron, and relations of Jamal Khashoggi, a critic of Saudi Arabia’s government who was murdered in the Saudi consulate in Istanbul in October 2018.
NSO Group has also been ordered to pay Meta $444,000 in damages.
The awards come after after a six-year battle between the US social media giant and the Israeli surveillance firm.
“The jury’s decision to force NSO to pay damages is a critical deterrent to this malicious industry against their illegal acts aimed at American companies,” Meta said.
“We firmly believe that our technology plays a critical role in preventing serious crime and terrorism and is deployed responsibly by authorised government agencies,” NSO said in a statement.
WhatsApp’s success in the case opens up NSO to potential legal action from other technology giants whose platforms were targeted with Pegasus spyware.
