Your pen-testing friend sent you this file from their last job - https://github.com/openctf/openctf-2015-dc23/blob/master/challange_downloads/ffbank-8a84d2299c58b2a1c30e133d8223fd9d?raw=true

[this challenge also has a hosted component, not currently available online]
[free hint: there are easy ways to solve the challenge, which are slow, and more difficult ways, which are faster]