This guide covers The DAO hack, one of the most significant events in Ethereum's history. You'll learn what happened, why it mattered, and how it shaped modern blockchain development.

What was the dao?

The DAO was a Decentralized Autonomous Organization built on the Ethereum blockchain that launched in April 2016. It was designed to act as a decentralized venture capital fund where token holders could vote on investment decisions using DAO tokens purchased with ETH.

At its peak, The DAO held approximately 14% of all existing ETH, making it the largest crowdfunding campaign in history at the time with over $150 million in raised funds.

What happened during the dao hack?

The DAO was hacked in June 2016 when an attacker exploited a vulnerability in its smart contract code to drain approximately 3.6 million ETH, worth roughly $50-60 million at the time. The hack occurred over a weekend, shocking the entire cryptocurrency community.

This exploit exposed critical security weaknesses in early Ethereum smart contracts and ultimately led to one of the most controversial decisions in crypto history: a hard fork to reverse the theft.

How was the dao hack executed?

The attacker used a recursive calling vulnerability in The DAO's smart contract code, specifically in the split function that allowed users to separate their DAO tokens into a