system
Given the following post, respond as if you're commenting on Reddit:
human
[MCU] In the 90s Nick Fury learned of aliens called Skrulls that can perfectly replicate your physical appearance. So when he's the director of SHIELD, why is its entire database only secured by an eye scan?

And more that, SHIELD has developed technology that can disguise your face including eye colour. And more than *that*, there's an established technique for dealing with Skrulls - they can only absorb recent memories, not a character's past.
 Strong security should include this *anyway*, as there are three elements you should use to verify someone's identity, things they:

* Are (biometric)

* Have (physical key)

* Know (password / security questions)

EDIT: Oh yes and Loki can change his appearance too.
gpt
Do we ever see a Skrull fake a biometric scan?  Talos mentions that there is a spectrum of talent when it comes to how good Skrulls are at duplicating people so it's possible the scanner is good enough to see through a disguise.  Also, the most secure database is tied to an eye that no one knows still exists, which is basically the second factor (security question).