Moscow's blockchain voting system cracked in August 2019

Dear community,

They said that Moscow’s blockchain voting system that used Ethereum as the basis for their platform was cracked in August

https://www.coindesk.com/moscow-blockchain-voting-system-completely-insecure-says-researcher
Does anybody know in detail about the situation? I am just guessing that they use Ethereum blockchain codes and then modified the encryption part for their own case. And due to that weakness in encryption that their system was cracked. Am I right?
Thank you so much for your help!
Crystal