Crypto wallet drainer: what it is and how to defend against it

A new category of malicious tools has been gaining popularity with crypto scammers lately: crypto wallet drainers. This post will explain what crypto drainers are, how they work, what makes them dangerous — even for experienced users — and how to defend against them.

What a crypto (wallet) drainer is

A crypto drainer — or crypto wallet drainer — is a type of malware that’s been targeting crypto owners since it first appeared just over a year ago. A crypto drainer is designed to (quickly) empty crypto wallets automatically by siphoning off either all or just the most valuable assets they contain, and placing them into the drainer operators’ wallets.

As an example of this kind of theft, let us review the theft of 14 Bored Ape NFTs with a total value of over $1 million, which occurred on December 17, 2022. The scammers set up a fake website for the real Los Angeles-based movie studio Forte Pictures, and contacted a certain NFT collector on behalf of the company. They told the collector that they were making a film about NFT. Next, they asked the collector if they wanted to license the intellectual property (IP) rights to one of their Bored Ape NFTs so it could be used in the movie.

According to the scammers, this required signing a contract on “Unemployd”, ostensibly a blockchain platform for licensing NFT-related intellectual property. However, after the victim approved the transaction, it turned out that all 14 Bored Ape NFTs belonging to them were sent to the malicious actor for a paltry 0.00000001 ETH (about US¢0.001 at the time).

The scheme relied to a large extent on social engineering: the scammers courted the victim for more than a month with email messages, calls, fake legal documents, and so on. However, the centerpiece of this theft was the transaction that transferred the crypto assets into the scammers’ ownership, which they undertook at an opportune time. Such a transaction is what drainers rely on.

How crypto drainers work

Today’s drainers can automate most of the work of emptying victims’ crypto wallets. First, they can help to find out the approximate value of crypto assets in a wallet and identify the most valuable ones. Second, they can create transactions and smart contracts to siphon off assets quickly and efficiently. And finally, they obfuscate fraudulent transactions, making them as vague as possible, so that it’s difficult to understand what exactly happens once the transaction is authorized.

Armed with a drainer, malicious actors create fake web pages posing as websites for cryptocurrency projects of some sort. They often register lookalike domain names, taking advantage of the fact that these projects tend to use currently popular domain extensions that resemble one another.

Then the scammers use a technique to lure the victim to these sites. Frequent pretexts are an airdrop or NFT minting: these models of rewarding user activity are popular in the crypto world, and scammers don’t hesitate to take advantage of that.

Also commonplace are some totally unlikely schemes: to draw users to a fake website, malicious actors recently used a hacked Twitter account that belonged to a… blockchain security company!

Scammers have also been known to place ads on social media and search engines to lure victims to their forged websites. In the latter case, it helps them intercept customers of real crypto projects as they search for a link to a website they’re interested in. Without looking too closely, users click on the “sponsored” scam link, which is always displayed above organic search results, and end up on the fake website.

Then, the unsuspecting crypto owners are handed a transaction generated by the crypto drainer to sign. This can result in a direct transfer of funds to the scammers’ wallets, or more sophisticated scenarios such as transferring the rights to manage assets in the victim’s wallet to a smart contract. One way or another, once the malicious transaction is approved, all the valuable assets get siphoned off to the scammers’ wallets as quickly as possible.

How dangerous crypto drainers are

The popularity of drainers among crypto scammers is growing rapidly. According to a recent study on crypto drainer scams, more than 320,000 users were affected in 2023, with total damage of just under $300 million. The fraudulent transactions recorded by the researchers included around a dozen — worth more than a million dollars each. The largest value of loot taken in a single transaction amounted to a little over $24 million!

Curiously, experienced cryptocurrency users fall prey to scams like this just like newbies. For example, the founder of the startup behind Nest Wallet was recently robbed of $125,000 worth of stETH by scammers who used a fake website promising an airdrop.

How to protect against crypto drainers

• Don’t put all your eggs in one basket: try to keep only a portion of your funds that you need for day-to-day management of your projects in hot crypto wallets, and store the bulk of your crypto assets in cold wallets.
• To be on the safe side, use multiple hot wallets: use one for your Web3 activities — such as drop hunting, use another to keep operating funds for these activities, and transfer your profits to cold wallets. You’ll have to pay extra commission for transfers between the wallets, but malicious actors would hardly be able to steal anything from the empty wallet used for airdrops.
• Keep checking the websites you visit time and time again. Any suspicious detail is a reason to stop and double-check it all again.
• Don’t click on sponsored links in search results: only use links in organic search results – that is, those that aren’t marked “sponsored”.
• Review every transaction detail carefully.
• Use companion browser extensions to verify transactions. These help identify fraudulent transactions and highlight what exactly will happen as a result of the transaction.
• Finally, be sure to install reliable security on all devices you use to manage crypto assets.

By the way, Kaspersky solutions offer multi-layered protection against crypto threats. Be sure to use comprehensive security on all your devices: phones, tablets, and computers. Kaspersky Premium is a good cross-platform solution. Check that all basic and advanced security features are enabled and read our detailed instructions on protecting both hot and cold crypto wallets.