The Evolution of Drainer Attacks: From Simple Approvals to Wallet Takeovers

TLDR: Modern crypto drainers have moved far beyond basic phishing, now leveraging advanced smart contract abuse and DaaS models to automate asset theft. Attackers are actively exploiting EIP-2612 permit functions and the new EIP-7702 standard to bypass traditional approval warnings. Security researchers and developers must prioritize auditing token approval flows and implementing real-time transaction simulation to defend against these increasingly automated, high-impact campaigns.

Cryptocurrency drainers are no longer just a nuisance for retail users; they have become a highly organized, professionalized industry. What started as simple, manual phishing campaigns targeting basic ERC-20 token approvals has evolved into a sophisticated, multi-chain ecosystem. Attackers now operate with the efficiency of a legitimate SaaS company, complete with leaderboards, affiliate incentives, and rapid infrastructure iteration. For anyone performing security research or penetration testing in the Web3 space, understanding these mechanics is no longer optional.

The Mechanics of Modern Draining

At the core of a drainer attack is the manipulation of user trust to gain authorization for asset transfers. The most common entry point remains the setApprovalForAll function in ERC-721 and ERC-1155 contracts. By tricking a user into signing this transaction, an attacker gains full control over the victim's entire NFT collection.

The evolution here is in the delivery and the payload. Attackers are increasingly moving toward EIP-2612 permit function abuse. Unlike standard approvals that require an on-chain transaction and gas fees, permit functions allow for gasless approvals via off-chain signatures. A victim signs a seemingly innocent message, and the attacker later broadcasts that signature to the network, paying the gas themselves to drain the wallet. This removes the friction that previously alerted users to suspicious activity.

Looking ahead, the EIP-7702 standard introduces even greater risk. By allowing an externally owned account to temporarily act as a smart contract, it opens the door for full wallet takeovers. Once a user signs a malicious message, the attacker can effectively replace the wallet's logic, turning a standard account into a contract that executes arbitrary, harmful transactions.

The DaaS Industrial Complex

Drainer-as-a-Service (DaaS) platforms have commoditized these attacks. In the past, a threat actor needed significant development expertise to craft a functional drainer. Today, they simply sign up for a DaaS provider like the now-defunct Inferno Drainer. These platforms provide the phishing templates, the malicious contract backends, and the obfuscation tools required to bypass basic security filters.

These services operate on a revenue-share model, typically taking 20% to 30% of the stolen assets. To keep their "clients" motivated, they implement gamification features like leaderboards that track the most successful phishers. This creates a feedback loop where attackers are constantly testing new social engineering vectors—such as fake copyright infringement emails or compromised Discord servers—to increase their volume and climb the rankings.

Defensive Realities for Pentesters

When you are auditing a project or conducting a red team engagement, your focus should be on the user's interaction with the wallet. If a dApp requires a signature, is it clear what that signature authorizes? Many developers fail to implement proper transaction simulation, which is the only reliable way to show a user exactly what will happen to their assets before they sign.

Tools like Blockaid have become essential in this space. They provide real-time simulation and risk assessment for transactions, effectively flagging malicious interactions before they hit the blockchain. During an engagement, test the dApp's integration with these security providers. If the dApp allows a user to sign a transaction without a clear, human-readable breakdown of the assets being moved, you have found a critical OWASP A01:2021-Broken Access Control vulnerability.

Recovery and Incident Response

If you are investigating a compromise, time is your greatest enemy. The first step is to check the transaction history on a block explorer like Etherscan. If the stolen funds are in a stablecoin like USDC or USDT, you have a narrow window to contact the issuer, such as Circle or Tether, to request a freeze.

While this is not guaranteed, providing a police report significantly increases the likelihood of a positive outcome. Simultaneously, use services like Revoke.cash to identify and cancel any remaining malicious approvals. Many users are unaware that they may have signed an approval months ago that remains active.

The landscape of Web3 security is shifting toward automated, high-speed exploitation. Attackers are no longer waiting for manual errors; they are building systems that turn user signatures into automated theft. As a researcher, your value lies in identifying these gaps in the user experience before the DaaS platforms do. Stop looking for simple bugs and start looking at the trust assumptions in the signature flows your applications rely on. The next major exploit will likely be hidden in a signature that looks perfectly valid to the average user.