A security researcher looks to have discovered an Achilles heel in the way millions of Android phones perform encryption, leaving these mobile devices potentially vulnerable to advanced hacking techniques.

The problem specifically exists in Android phones running on certain Qualcomm Snapdragon processors. Consequently, Qualcomm and OEMs could comply with law enforcement to break Full Disk encryption if they wished to cooperate, researcher Gal Beniamini wrote in a blog post.

Essentially, a critical program designed to help protect devices' encryption keys runs in a segmented “TrustZone” within the Qualcomm processor itself, which is supposed to be more secure than the Android operating system. However, a kernel vulnerability within TrustZone is in essence leaking the encryption keys, allowing adversaries to use these keys off-device to break Full Disk Encryption via brute-force attack, without fear of triggering the mechanism that would normally erase files after a certain number of guesses.