San Francisco, Dec 22 : A day after it was disclosed that Israeli intelligence firm NSO Group hacked iPhones of 36 Al Jazeera journalists, top tech giants like Microsoft Google, Cisco, VMware and the Internet Association filed an amicus brief in a legal case brought by Facebook-owned WhatsApp against the NSO Group. The NSO Group is currently embroiled in a legal battle with Facebook, which last year accused that the Israeli spyware maker used Pegasus in WhatsApp to infect some 1,400 people, mostly celebrities, journalists and human rights activists. Facebook has submitted detailed proof in the court about the Israeli company and the allegedly hacking into at least 1,400 WhatsApp users via its controversial surveillance software. Tom Burt, Corporate Vice President, Customer Security and Trust at Microsoft, said late on Monday that the NSO Group's business model is dangerous. "One of these 21st-century mercenaries, called the NSO Group, is attempting to cloak itself in the legal immunity afforded its government customers, which would shield it from accountability when its weapons inflict harm on innocent people and businesses," he emphasised. Burt said that private companies should remain subject to liability when they use their cyber-surveillance tools to break the law, or knowingly permit their use for such purposes, regardless of who their customers are or what they're trying to achieve. "That's why today we filed an amicus brief Â? along with Cisco, GitHub, Google, LinkedIn, VMWare and the Internet Association Â? in a legal case brought by WhatsApp against the NSO Group," he said. "We hope that standing together with our competitors today through this amicus brief will help protect our collective customers and global digital ecosystem from more indiscriminate attacks". Researchers from Canada-based Citizen Lab have revealed that the Pegasus spyware compromised iPhones of dozens of journalists. In July and August this year, government operatives used NSO Group's Pegasus spyware to hack 36 personal phones belonging to journalists, producers, anchors, and executives at Al Jazeera. The personal phone of a journalist at London-based Al Araby TV was also hacked, said researchers in a report that came out on Sunday. The NSO Group sold Pegasus to governments, which could be installed on a device simply by calling the device via WhatsApp and the device's owner did not even have to answer. "Even if the tools are sold to governments who use them for narrowly targeted attacks, there are a variety of ways they can still fall into the wrong hands," said Burt. According to him, private-sector companies creating these weapons are not subject to the same constraints as governments. "Private actors like the NSO Group are only incented to keep these vulnerabilities to themselves so they can profit from them, and the exploits they create are constantly recycled by governments and cybercriminals once they get into the wild". /IANS