Are you running an application in a cloud environment like Amazon’s EC2? Cloud providers usually offer a nifty way to manage credentials: Internal Meta Data Services (IMDS). For AWS, the IMDS listens on 169.254.169.254. 169.254/16 being link-local only, only code running on the host itself can reach it, and your code can use this service to retrieve credentials. Or, well, any code running on the host can.
Article Link: log4shell and cloud provider internal meta data services (IMDS)