Law enforcement agencies are known to use the GrayKey tool from Grayshift to break into locked iPhones. Depending on the passcode length, the entire process can take a few hours to a few days. It turns out though that law enforcement agencies are using another tool from Grayshift that can silently log an iPhone’s passcode when it is being unlocked by its owner.

The spyware called Hide UI has been around for a year and it is largely used as a Plan B by law enforcement agencies in case the GrayKey tool is unable to unlock a locked iPhone or takes a long time to do so. Interestingly, Grayshift has been low-key about Hide UI and does not even talk about it in its marketing materials. Law enforcement agencies are also made to sign an NDA to ensure that details about Hide UI are not revealed. Features related to Hide UI are also detailed to potential customers after they sign the non-disclosure agreement.

The process requires Hide UI to be installed on the iPhone and then set up such a scenario that the suspect ends up unlocking their iPhone. The passcode is then logged and stored in a text file that can be extracted by plugging the device into GrayKey. After this, law enforcement agencies can unlock the device and extract all data from it.

“It’s great technology for our cases, but as a citizen I don’t really like how it’s being used. I feel like sometimes officers will engage in borderline and unethical behavior,” alaw enforcement official said.

As per another law enforcement official though, Hide UI is buggy and does not always work properly. In many cases, it is simply easier to get the suspect to hand over the passcode of their iPhone during interrogation.

A screenshot of Hide UI also reveals that it will disable airplane mode and prevent anyone from wiping the iPhone on which it is installed.

Many analysts do fear that law enforcement agencies are using Hide UI without a proper warrant, especially since law enforcement agencies and GrayShift have been very low-key about it.