If your phone is infected with spyware like Pegasus, it's extremely difficult to know — even if you're Jeff Bezos.
The phone probably won't start suddenly overheating or ripping through battery life. If that were the case, "then the people who did it have not done their jobs right," Scott-Railton said.
In fact, if you're not a cybersecurity researcher, it's nearly impossible to know.
"It's quite tricky because the software is of course designed to be hard to find," Scott-Railton said. "What we did in the first instance was we actually captured the network traffic going into the phone after the [link] was clicked, and that gave us the infection."
Unless you're monitoring the network traffic going into your smartphone and also are savvy enough to know what type of network traffic could demonstrate malicious behavior, it's unlikely that you'd catch spyware like Pegasus running on your device.
That's exactly how investigators identified that Bezos phone was hacked. "The forensic analysis found that ... massive and (for Bezos' phone) unprecedented exfiltration of data from the phone began, increasing data egress suddenly by 29,156 per cent to 126 MB," a statement from the UN said. "Data spiking then continued undetected over some months and at rates as much as 106,032,045 per cent (4.6 GB) higher than the pre-video data egress baseline for Mr. Bezos' phone of 430KB."