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Cyberattackers are targeting users of the OpenSea nonfungible token (NFT) platform with a phishing attack that lures users with the potential sale of items listed on the marketplace. The aim? Draining their cryptocurrency wallets dry.

Researchers at Cofense discovered the campaign, in which adversaries impersonate the OpenSea website and claim a user has a new offer on a listing on the site to try to bait them into clicking on a malicious link.

"The goal of the phishing scheme is to get recipients to connect their crypto wallets to the phishing page, which will drain their wallets," Cole Adkins of the Cofense Phishing Defense Center wrote in a post. "The phish presents itself as an offer on an NFT the recipient has listed on OpenSea, in hopes they will click on it and connect their wallet once redirected."

OpenSea is the largest marketplace for NFTs and thus "the go-to platform for many entry-level NFT enthusiasts looking to enter the crypto collectible market," who are likely unaware of the common tactics of phishers and thus can easily be fooled, he wrote.

The campaign demonstrates the speed with which attackers are targeting new and emerging technologies like NFT — which held little interest for people until OpenSea was launched in 2017 —  with custom campaigns tailored to their particular interests, he said. OpenSea marketplace currently has more than 2 million users with at least one transaction on the site, many of them enterprise users.

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OpenSea Brand Impersonation for the Phishing Lure

The attack begins when targeted victims receive an email that appears to come from OpenSea. To a savvy user, it would be a clear phish, as the sender address is "administrator[at]motordna[dot]io," and thus unrelated to the NFT marketplace. However, the branding in the content of the email mimics OpenSea using a look that's similar to the site, and it could fool someone not keeping an eye out for phishing clues, according to Cofense.

"By branding the email as OpenSea and employing the same email format used for an actual notification from the OpenSea NFT marketplace, the threat actor hopes to ease the recipient’s suspicion so they will click the button in the email body," Adkins wrote.

Recipients are prompted to hit an "Access Now" button to direct to a purported offer that's come on one of their items on the marketplace, demonstrating the use of social engineering that adds urgency and aims to instill excitement at the potential of a sale, he wrote.

Users that click on the button are directed to a fake OpenSea webpage that's also been designed by attackers to appear legitimate. The page shows that an offer has been made on an NFT owned by the victim and they must accept it quickly by connecting to their crypto wallet via a "Connect Wallet" button, or else lose their chance at a sale. Clicking presents the user with multiple ways to access the wallet, such as via a QR code or signing in with credentials. Once this step is complete, an attacker can control the wallet and any credentials associated with it.

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NFT in the Crosshairs

The campaign is not the first time OpenSea has been targeted by a potential threat actor. A couple of years ago, an employee of one of the marketplace's email vendors, Customer.io, accessed and downloaded the company's email list, ostensibly for future phishing attacks. The cybercriminal group Marko Polo also has impersonated OpenSea as a way to target its users for fraud.

While NFT hasn't quite gone mainstream yet, attackers are increasingly targeting those interested in the novel technology to expand their attack surface. These attacks will likely ramp up as the technology gains popularity, according to Cofense. "This … highlights why recipients must stay vigilant and up to date with common phishing threats in order to protect their assets," Adkins wrote.

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Cofense recommends that users of OpenSea and other NFT marketplaces use the same online hygiene as any other e-commerce user when navigating access to their accounts. Best practices for protecting assets include avoiding clicking on links in emails from addresses or users they don't recognize, and learning to recognize common phishing and social-engineering tactics. The company also recommends that OpenSea users should check the sender field of any email that purports to be from the marketplace for suspicious-looking addresses that could alert them to foul play.