You can read more about the story from their blog post here:
https://blog.blocktix.io/blocktix-and-the-parity-multisig-hack-81c1b2aefbd6
Basically, there was a Parity Multisig wallet exploit that allowed hackers to access contract wallets. Blocktix had one of their older ETH wallets hacked and lost 1M in ICO investments.
When looking at this, a few lessons are to be learned.
Firstly, ETH continues to face a lot of attacks from hackers, and understandably so. This is really to be expected and demonstrates a pretty natural progression of technology as the kinks get worked out and platforms secured. It also shows the overall interest and trajectory that we've seen in Ethereum and crypto as a whole. And, while it is unfortunate, it's really just the current state of affairs.
This does not demonstrate a security vulnerability in Ethereum, but rather, an issue with multisig on Parity.
Secondly, ICOs and crypto projects need to learn from this and start cycling contract addresses to limit potential exposure. By cycling contract addresses with set limits, of say, 1k ETH, it minimizes some of your potential attack vectors.