Examples of the Best Answers
There were several times where I used good judgment and logic to solve a problem relatively quickly while working with production support to help triage a problem causing an outage, or customer impact, spam, fraud, etc. In my project, the backend job identified that a customer having a high volume of account recharge being done on an account via PINs. This could be legitimate or this could be an indication of fraud.
I started to study the customer account and its transactions, I did see a lot of money adds in relative in a day but the usage is not there. Also there if there were 10 successfully attempts there were almost 5 failures as well. All such request very coming from mobile phones. This could have been fat fingering, but I had a hunch and I checked, I saw that the PIN numbers were way different each time. So I started looking at the raw application logs, and as suspected, I not only saw a these 15 so request but I was able to trace a few thousand requests in the attempts, with a pattern going back 2-3 days. This could not not be possible via human interaction, but via a bot program. After digging deeper, I uncovered that the bot program was trying the random number of pins via the API, and try to find a pin that was not valid. Then using that PIN, it was trying to add money to the account. We saw the traffic coming from 1 IP and web suspend the IP and blocked the account to take care of it.