Bitcoin traded in the $76,300 range on Thursday after Binance confirmed a security breach that the exchange estimates at $6.3 billion in total impact, a figure that would place the incident among the largest cryptocurrency thefts on record.

Earlier in the session, bitcoin touched a 24-hour high of $81,890 before the selloff, which came as millions of dollars in leveraged long positions were liquidated. Liquidations force the closure of leveraged positions whose collateral no longer covers potential losses, and clustered liquidations can amplify short-term price swings in both directions.

Compromised Laptop Under Investigation

In a post on X, the exchange said its initial investigation suggests the incident may have involved a compromised DevOps engineer's laptop. The attacker reportedly gained access to a service container and submitted unauthorized withdrawal transactions. Binance said it has found no evidence of a wallet private key leak.

"The estimated total impact sits at around 6.3B. We have worked with blockchain partners to freeze affected assets, with ~3 billion frozen on-chain so far. Binance will cover all losses from the SAFU fund and the company's funds. User funds are safe. We will also publish an updated Proof of Reserves once the remediation is complete," Binance said in the post.

SAFU, short for Secure Asset Fund for Users, is an emergency reserve Binance set up to cover user losses in security incidents, and proof-of-reserves reports are published to show that an exchange holds the customer assets it claims. The revised $6.3 billion estimate is higher than earlier figures, which ranged from $2.7 billion to $5.8 billion. The exchange said it has worked with blockchain partners to freeze affected assets, with about $3 billion frozen on-chain so far.

"We will share a detailed technical post-mortem once the investigation is complete and the facts are verified," the company said. With no timeline announced, the post-mortem, the promised updated Proof of Reserves and any reopening of deposits and withdrawals are the key milestones for users following the remediation.

Stablecoin Issuers Freeze Funds

Tether CEO Paolo Ardoino said earlier that the company had frozen more than 1.567 billion USDT, while Circle also froze USDC tied to the suspected attacker. Both issuers have freeze functions built into their tokens, letting them block transfers at specific addresses. Co-founder Yi He wrote in a post on X that user funds are safe and that Binance will cover all hacking losses.

Concerns over a potential hack surfaced after a user noticed more than $2.7 billion in assets, including Ethereum and stablecoins issued by Tether and Circle, being moved from a Binance wallet to an external account under suspicious circumstances.

Withdrawals Suspended During Security Checks

Deposits and withdrawals remain suspended while the exchange conducts security checks, freezes funds and works with law enforcement. Binance said it has revoked the affected address authorization and is working to confirm the identities of those responsible.

Aave reportedly froze lending markets to block the suspected attacker from borrowing against the stolen funds. Binance.US said the incident does not affect its platform.

The company has not released a timeline for the full post-mortem. Until then, the exchange is asking users to rely only on official Binance channels for updates.

Changpeng Zhao, Binance's former CEO, tweeted on X during the exploit: "User funds are safe! It does look like a hack on Binance. Appreciate the quick freeze from [Tether and Circle]. I don't manage Binance (.com) anymore, but as a shareholder, I expect all user funds will be fully covered."

Market Reaction

Bitcoin dropped to $76,301 as news of the hack was circulating. The asset is currently trading near $77,800.

This article was first published by Bitcoin Magazine and is written by Micah Zimmerman.