Today in crypto, Coinbase rejected a $20 million ransom demand after insiders leaked user data in a phishing scheme, but the exchange could face a bill of up to $400 million. Huione Guarantee, suspected as the world’s largest darknet marketplace, has shut down, citing a Telegram account purge that decimated its network, and US Commodity Futures Trading Commission (CFTC) commissioner Summer Mersinger is set to become the next CEO of the crypto advocacy group Blockchain Association.
Coinbase faces $400 million bill after insider phishing attack
Coinbase, the world’s third-largest cryptocurrency exchange, was hit by a $20 million extortion attempt after cybercriminals recruited overseas support agents to leak user data, the company said.
According to a May 15 blog post, Coinbase said a group of external actors bribed and coordinated with several customer support contractors to access internal systems and steal limited user account data.
“These insiders abused their access to customer support systems to steal the account data for a small subset of customers,” Coinbase said, adding that no passwords, private keys, funds or Coinbase Prime accounts were affected.
Less than 1% of Coinbase’s monthly transacting users’ data was affected by the attack, the company said.
After stealing the data, the attackers attempted to extort $20 million worth of Bitcoin from Coinbase in exchange for not disclosing the breach. Coinbase refused the demand.
Coinbase said it will reimburse users who were tricked into sending cryptocurrency to phishing scammers, with expected remediation and reimbursement expenses ranging from $180 million to $400 million.
The crypto exchange disclosed the estimate in an 8-K filing with the US Securities and Exchange Commission on May 15, noting the expenses relate to “voluntary customer reimbursements” and other remediation efforts.
Telegram shuts the “largest darknet marketplace to have ever existed”
A major Chinese darknet marketplace suspected of facilitating crypto scams and cybercrime says it is ceasing operations after being targeted in a ban wave by the Telegram messaging service, upon which it operated.
The internet’s largest illicit marketplace, Haowang Guarantee, formerly Huione Guarantee, saw Telegram’s ban thousands of its associated accounts on May 13.
“Since all our NFTs, channels and groups were blocked by Telegram on May 13, 2025, Haowang Guarantee will cease operations from now on,” read the notice on the marketplace website.
A report from Wired said that this involved banning thousands of accounts and usernames that served as the infrastructure for the crypto crime marketplace and its vendors.
Telegram spokesperson Remi Vaughn told the outlet, “communities previously reported to us by WIRED or included in reports published by Elliptic have all been taken down,” before adding that “criminal activities like scamming or money laundering are forbidden by Telegram’s terms of service and are always removed whenever discovered.”
CFTC commissioner will step down to become Blockchain Association CEO
Summer Mersinger, one of four commissioners currently serving at the US financial regulatory body Commodity Futures Trading Commission (CFTC), will become the next CEO of the digital asset advocacy group the Blockchain Association (BA).
In a May 14 notice, the Blockchain Association said its current CEO, Kristin Smith, would step down for Mersinger on May 16, allowing an interim head of the group to work until the CFTC commissioner assumes the role on June 2. Though her term at the CFTC was expected to last until April 2028, the BA said Mersinger is set to leave the agency on May 30.
The departure of Mersinger, who has served in one of the CFTC’s Republican seats since 2022, opens the way for US President Donald Trump to nominate another member to the financial regulator. Rules require that no more than three commissioners belong to the same political party.
Like the Securities and Exchange Commission, the CFTC is one of the significant US financial regulators whose policies impact digital assets. Lawmakers in Congress are currently working to pass a market structure bill to clarify the roles each agency could take in overseeing and regulating crypto.
New leadership at the Blockchain Association had been expected since Smith announced her departure on April 1 to become the next president of the Solana Policy Institute.