A massive Ronin Network crypto hack has just occurred. According to experts, the $600 million hack was due to a lack of cybersecurity rather than a flaw in blockchain technology.

Ronin is a blockchain protocol that is linked to Axie Infinity. The NFT play-to-earn reached $4 billion in NFT sales, with more than 2.8 million players logging in daily. In a blog post, Ronin said that the hacker stole about $625 million in crypto, draining 173,600 ether and 25.5 million USDC. The hack was only detected a week later.

"A hack used to mean loss of passwords and usernames, but in the age of crypto, it means the loss of life savings," Ari Redbord, head of legal and government affairs at blockchain research firm TRM, told Insider. "Bank robbery at the speed of the internet."

Max Galka, CEO of crypto forensics firm Elementus, pointed to the lapsed DAO deal as a major oversight, noting that vulnerabilities arise when cryptocurrencies are stored inside chains rather than native blockchains.

"They never removed what was meant to be a temporary measure. It was an outright error," he told Insider.

According to the team behind the Ronin Network, the attack was socially engineered. In other words, the hacker targeted employees via emails or phishing websites, to gain access to the system.

"It was pure human error," Amber Ghaddar, founder of decentralized finance firm AllianceBlock, told Insider, adding that social engineering is one of the most common drivers of cybercrimes. 

"If consumers aren't protected from things like this, the industry is going to fail," she added.

Hackers will keep using social engineering until it stops being effective, but this isn't a reason to be skeptical of cryptocurrency as technology, said Redbord.

"Attacks like this are concerning, but I believe in the promise of crypto," Redbord said. "We need to focus on building out a trust layer in the crypto economy — anti-money laundering infrastructure, compliance controls, cybersecurity — so that people will interact with this new online financial system.