The provided sources discuss the serious threat of zero-click spyware attacks like those utilizing NSO Group's Pegasus and Intellexa's Predator malware. These attacks are particularly dangerous because they compromise devices, such as iPhones and Android phones, without requiring any user interaction, such as clicking a link or answering a call. The texts describe major incidents, including the 2019 WhatsApp breach and various iMessage vulnerabilities that allowed for remote code execution and data extraction, often targeting journalists and activists. In response to these sophisticated threats, Apple developed its Lockdown Mode to restrict device functionality and shrink the attack surface for a small number of high-risk users. The sources emphasize that while these exploits are highly valuable on the black market and difficult to detect, maintaining up-to-date software remains a critical defense against both known and zero-day vulnerabilities.