Bitcoin and crypto holders have been left reeling by an attack on cold hardware wallet Coldcard that's seen around $40 million worth of bitcoin stolen.

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The bitcoin price has dropped in the hours since the attack was discovered but it remains above its key $60,000 per bitcoin support level.

Now, fears are swirling that news of the attack could drive the bitcoin price lower, potentially sending it crashing under the $58,000 level it fell to at the end of June.

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Panic swept the bitcoin and crypto community last night after reports spread that almost 600 bitcoin worth around $40 million was stolen from hundreds of separate wallets that their owners had thought were secure.

In a matter of minutes, attackers drained some 500 Coldcard hardware wallets that used mostly single-signature security and had been affected by a bug that meant the wallets used predictable software-based key generation seeded by chip data rather than a sophisticated randomness generator.

Coldcard is a bitcoin-only hardware wallet created by the Canada-based Coinkite that keeps private keys offline, uses dual secure elements, and supports air-gapped transaction signing.

"Out of an abundance of caution, Coinkite is warning all users who generated a seed using a Mk3 on version 4.0.1 (March 2021) or any subsequent version that their funds may be at risk," Coinkite developers wrote in a blog post.

"We were unaware of the bug until today," they added, advising users to "proceed calmly, verify every step," and move their funds to a new wallet. "Updating the firmware does not repair a seed that was generated by affected firmware. A new seed must be generated and the funds migrated to the new wallet ... When migrating to a new key, calm and care should be applied. Rushing a wallet migration can create a more immediate risk than the issue you are trying to address."

The threat has spread to other hardware wallets due to the ability of wallets to import seeds.

"If you exported a seed generated in a vulnerable Coldcard, moving it to another wallet, then that same insecure seed is still affected," security researchers with Jack Dorsey's Block wrote in a blog post .

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The attack has fed fears that the widespread adoption of artificial intelligence tools will lead to the volume of attacks on bitcoin and crypto software increasing.

"The exploit is out in the wild, public attention is on it, and everybody has access to frontier LLMs [large language models]," a pseudonymous onchain analyst and prominent crypto skeptic using the handle @Pledditor posted to X. “I imagine there are dozens of hacking teams now researching how to exploit this. You are in a race against time.”

"I have a very bad feeling AI was involved in this unfolding situation with Coldcard’s being drained," X user Cobra, the pseudonymous co-owner and administrator of the prominent Bitcoin.org website, posted to X, adding bitcoin could collapse under $60,000 as a result.

"This will bring us down to $58,000 when the media get a hold of it," Cobra posted .