How to have a unique random number generated in a csv file every time without manual intervention?

I need to pass 10 digit alpha numeric random value (e.g. AUT******* where * denotes any random number) in a csv file.

Contents of csv file:

Code,Account1,Account2,Account3
AUT*******,ABC,DEF,GHI

This csv file will be uploaded in to a web application every time to perform some operation.

I need this value to be unique every time, before I upload the csv file to the web application so that web application considers the unique value for upload operation.

Manually we can do these steps, but I want to automate this process without any manual intervention. This is required for my Automation framework.

Please help me with some suggestion/possibilities?

Thanks, Siva