OpenSea Warns of Phishing Attacks Due to Data Breach

A third-party vendor’s employee misused their access to OpenSea’s customer data, the head of security said

article-image

Blockworks Exclusive Art by Axel Rangel

share

key takeaways

  • A Customer.io employee shared email addresses with an unauthorized external party
  • OpenSea warned users of fraudsters trying to impersonate the platform by using fake domain names

Collectibles platform OpenSea has alerted customers to a data breach after staff found email addresses were shared with an external party.

Head of Security Cory Hardman said in a blog post on Wednesday that an employee of Customer.io, OpenSea’s email delivery vendor, abused their access by downloading and externally sharing customer data. 

“If you have shared your email with OpenSea in the past, you should assume you were impacted,” he wrote. “We are working with Customer.io in their ongoing investigation, and we have reported this incident to law enforcement.”

The company further warned customers might face phishing attacks — attempts by cybercriminals posing as credible institutions with an aim to obtain sensitive information — by using a domain name similar to the official “opensea.io,” such as “opensea.org” or “opensae.io.”

Screenshots posted to Twitter show OpenSea notified customers about the data breach via email. Some users demanded compensation.

Loading Tweet..

Customer.io told Blockworks that the employee in question has been suspended and had access removed, pending an internal investigation. “We are working closely with OpenSea and are reviewing exactly how these email addresses were compromised,” a spokesperson for the vendor company said.

A similar incident occurred in March, when hackers breached third-party marketing vendor HubSpot to target large crypto stakeholders. NYDIG, Pantera Capital, BlockFi, Circle and Swan Bitcoin were among the affected companies.

OpenSea found itself in a sea of trouble thanks to another incident prior the data breach. The Department of Justice earlier this month charged its former head of product, Nathaniel Chastain, with insider trading in connection to non-fungible tokens (NFTs). He was charged with one count of wire fraud and another count of money laundering.

Chastain resigned from his position at OpenSea in September after he was suspected of profiting from inside information and purchasing NFTs before they were posted publicly.

OpenSea remains the leading marketplace by volume by a wide margin, with over six times the sales of the second-largest NFT marketplace over the past 30 days, according to data from DappRadar.


Start your day with top crypto insights from David Canellis and Katherine Ross. Subscribe to the Empire newsletter.

Explore the growing intersection between crypto, macroeconomics, policy and finance with Ben Strack, Casey Wagner and Felix Jauvin. Subscribe to the Forward Guidance newsletter.

Get alpha directly in your inbox with the 0xResearch newsletter — market highlights, charts, degen trade ideas, governance updates, and more.

The Lightspeed newsletter is all things Solana, in your inbox, every day. Subscribe to daily Solana news from Jack Kubinec and Jeff Albus.

Tags

Upcoming Events

Javits Center North | 445 11th Ave

Tues - Thurs, March 18 - 20, 2025

Blockworks’ Digital Asset Summit (DAS) will feature conversations between the builders, allocators, and legislators who will shape the trajectory of the digital asset ecosystem in the US and abroad.

recent research

Unlocked by Template.jpg

Research

The BitcoinOS team is the first to have developed and posted a ZK-compressed proof on the Bitcoin network. Other proof verification efforts have been limited to the Signet or testnet deployments. Their work has resulted in the development of BitSNARK, a software library for ZK-compressed fraud proofs on the Bitcoin network. The project aims to provide a horizontal scaling solution, offering a one-stop shop for teams interested in developing a rollup on Bitcoin. This approach shares similarities with the horizontal tech stack scaling in other ecosystems like Cosmos and Optimism, particularly in its focus on simplified verification, bridging standards, and lightweight interoperability.

/

article-image

A16z’s State of Crypto report shows that DeFi has the largest number of daily active addresses, with stablecoins following closely behind

article-image

G2 is delivering real-world performance breakthroughs at 50-100 Mgas/s, Conduit says

article-image

World Liberty Financial’s token sale debuted just as an absurd AI-fueled memecoin captured crypto’s attention

article-image

Coinbase hired History Associates in 2023 to assist in retrieving records from the SEC and FDIC

article-image

Hours after pledging to support Black men’s rights to safely invest in crypto, VP Harris’s Monday night speech mentioned blockchain zero times