Coinbase published a blog post Wednesday detailing its security infrastructure in response to the Binance hack that drained approximately $6.4 billion from the rival exchange last week. The U.S.-based exchange stated it was not affected by the attack and maintains more than 99% of customer assets in offline cold storage. The disclosure comes as the cryptocurrency industry faces heightened security scrutiny following the FBI's attribution of the Binance theft to North Korea's TraderTraitor group and subsequent security breaches at Brazil's Mercado Bitcoin and French bank Crédit Mutuel Arkéa.
Coinbase Details Multi-Layer Cold Storage Security Controls
Coinbase outlined several security layers protecting customer funds. Private keys for cold wallets are split into pieces and never fully reassembled, even when signing transactions. No single employee has standing access to the hot-wallet signing service. The exchange imposes strict limits capping how fast funds can move from cold to hot wallets, and unusual withdrawal spikes are held until staff review them. Coinbase can trigger "kill switches" that take signing keys offline entirely.
The company moves funds into internet-connected hot wallets only as customers need them. Sensitive actions require multiple approvals, and the system assumes employees will be targeted by phishing. Controls are designed so that a stolen password, session or device cannot be used on its own.
Coinbase reported customer assets are held 1:1 and are not lent out unless customers direct it to. The exchange disclosed $8.6 billion in cash and cash equivalents and $377 billion in assets on its platform as of Sept. 30. The company flagged artificial intelligence as a fast-changing threat and pledged further security investment.
Coinbase Discloses May 2025 Customer Support Bribery Incident
In May 2025, Coinbase disclosed that criminals bribed overseas customer support agents to steal personal data on less than 1% of its monthly transacting users. The attackers then demanded a $20 million ransom that Coinbase refused to pay.
Last week, Coinbase said a security incident at analytics vendor Amplitude exposed contact data for a "small subset" of customers, though funds were not affected.
Industry Faces Wave of Crypto Exchange Security Breaches
The Binance theft rattled the cryptocurrency industry. Blockchain analytics firm Elliptic found that the laundering spanned approximately 12,000 wallets in under four days. Stablecoin issuers froze about 44% of the stolen funds.
Brazil's Mercado Bitcoin halted withdrawals after a $40 million hack. French bank Crédit Mutuel Arkéa confirmed a cyberattack that led to a $133 million crypto theft.
FAQ
What percentage of Coinbase customer assets are kept in cold storage?
Coinbase keeps more than 99% of customer assets in offline cold storage, meaning wallets that cannot be reached over the internet. Funds are moved into internet-connected hot wallets only as customers need them.
How much did attackers steal from Binance last week?
Attackers drained approximately $6.4 billion from Binance's hot wallets last week. The FBI attributed the theft to North Korea's TraderTraitor group, and blockchain analytics firm Elliptic found the laundering spanned approximately 12,000 wallets in under four days.
