Smart Contract Engineering: “$500K Drain from Liquidity Provider Balancer”

[vestings]

https://www.coindesk.com/hacker-drains-defi-liquidity-balancer

[microtherion]

Having read both the coindesk article and the medium post, I still don't understand how this attack worked. Can somebody ELI5?

[rhabarba → microtherion]

There was no attack. Someone read the protocol specs and used them within the allowed borders of said protocol specs to tell the protocol to generate some revenue for them. End of story.

[microtherion → rhabarba]

Yes, but how did this generate revenue for them?