> In a company of that size it should be actually impossible for a transaction like this to occur without clearly documented processes to ingest, review, authorise and pay transactions.

Oh, my sweet summer child. The larger the organization, the more dysfunctional it becomes.

See How this scammer used phishing emails to steal over $100 million from Google and Facebook

https://www.cnbc.com/2019/03/27/phishing-email-scam-stole-10...