A user with significant EVM holdings has unknowingly granted approval to a contract that later turns malicious. Thousands of dollars in tokens drain within minutes because a previously legitimate service changed its permissions or was compromised. The user’s private keys never left their control, yet their assets disappeared anyway. This scenario reflects a specific vulnerability in self-custodial blockchain interaction: token approvals create standing permissions that can be exploited long after the initial transaction. The question is not whether this risk exists—it does—but whether available tools actually prevent it or merely create the appearance of control.
Two approaches have emerged for managing this risk. Etherscan, the dominant blockchain explorer, provides an “Approvals” dashboard where users can view and revoke token permissions on the mainnet and other EVM networks. Rabby Wallet, a self-custodial browser extension and mobile application, integrates approval management directly into its interface and combines it with transaction simulation to warn users before dangerous interactions occur. Both claim to protect users; neither works if the user ignores the warnings or fails to understand what approvals actually do. The practical question is which tool catches more real-world wallet drains and which one is more likely to be used correctly under pressure.
How token approvals work and why they create persistent risk
When a user interacts with a decentralized application on an EVM blockchain, they often grant permission for a smart contract to transfer tokens on their behalf. This is not a one-time transaction. An approval creates a standing allowance—an amount the contract is authorized to move without asking again. A user might approve a decentralized exchange to spend up to unlimited USDC, a lending protocol to access their ETH, or a farming contract to handle their staked tokens. Each approval is recorded on the blockchain and persists until explicitly revoked.
The vulnerability emerges when that contract is later exploited, its permissions are misused, or the service itself becomes an attack vector. A legitimate protocol can have its authorization compromised through a private key leak, a smart contract upgrade that introduces a flaw, or a compromised frontend. A user who has approved the contract remains vulnerable until they actively revoke that permission. The recovery of lost funds is impossible because the blockchain does not reverse transactions. A self-custodial wallet can help users manage these permissions, but it cannot protect against them retroactively.
This is why token approvals are distinct from asset custody. A self-custodial wallet keeps private keys local and prevents a service from stealing the keys. Token approvals, by contrast, are permissions that the user themselves authorized. The wallet software can help users avoid granting dangerous permissions in the first place and can help them revoke approvals before they are exploited. But the moment an approval is granted, the user must actively monitor and manage it.
The practical scale of this risk is significant. Approval-based exploits have been responsible for hundreds of millions in losses across Ethereum and other EVM networks. Users who understand the risk can mitigate it through tools like Etherscan or through integrated wallets. Users who do not understand it are vulnerable regardless of which tool is available. This is a user education problem as much as a software design problem.
Etherscan’s Approvals dashboard: comprehensive but passive
Etherscan’s “Approvals” section is the most widely used tool for checking token permissions. A user can connect their wallet address, view all approvals granted to any token, see the contract receiving the permission, and revoke approvals one at a time. The interface is straightforward: a list of tokens, the addresses of approved contracts, and a “Remove Approval” button for each entry. This is the first place many users look when they become aware of the approval risk.
The strength of this approach is completeness and standardization. Etherscan works across all EVM chains where it is deployed. A user can audit all their approvals without installing a new wallet or browser extension. The revocation is transparent on the blockchain; it is not hidden behind a wallet interface. An advanced user can examine the contract code, inspect the ABI, and understand exactly what permissions were granted. There is no proprietary system or opacity.
The weakness is that Etherscan is reactive, not preventive. A user visits Etherscan only when they remember to, or when they have already been compromised and are searching for a solution. By that time, the malicious contract has already executed the drain. Even users who regularly audit their approvals on Etherscan can fall victim to a newly compromised protocol or a very fast exploit that drains funds within minutes. Etherscan can help recover from this situation by revoking the dangerous contract, but it cannot prevent it. Additionally, revoking approvals on Etherscan requires the user to manually initiate each transaction, pay gas fees, and wait for confirmation—a process that can be tedious when a user has accumulated dozens of approvals across multiple tokens and protocols.
Rabby Wallet’s integrated approval manager and transaction simulation
A Rabby Wallet user experiences approval management differently because the wallet software sits between the user and every dApp interaction. When a dApp requests an approval, Rabby displays a transaction simulation that shows what the dApp will actually do. This simulation reveals the token, the contract receiving the permission, and the amount authorized. The user can see in human-readable terms whether they are granting unlimited access or a specific amount. Many dangerous phishing attempts or malicious dApps become visible at this stage because the simulation reveals unexpected contract calls or token transfers.
Beyond initial protection, Rabby’s interface includes an approval management section where users can view and revoke permissions without leaving the wallet. Because Rabby is self-custodial and runs locally, the wallet can also apply custom risk warnings. If a user attempts to visit a known phishing domain or interact with a contract flagged for exploitative behavior, Rabby can alert them before they grant approval. An open source wallet like Rabby makes its risk detection logic available for inspection; users can review the code to understand what conditions trigger warnings.
The power of this approach is that it is integrated into the transaction approval flow itself. A user does not need to remember to check Etherscan or visit a separate tool. The warning appears at the moment of decision. This makes transaction simulation a critical defense because it catches the attempt before the blockchain is involved. A user can see the simulation, realize something looks wrong, and reject the transaction entirely. This is prevention rather than remediation.
The limitation is that Rabby’s risk detection is only as good as its warning system. If a contract is brand new and not yet flagged as malicious, Rabby may not recognize it as dangerous. If a user ignores the warning or does not understand it, the protection is ineffective. A phishing site that mimics a legitimate dApp domain can still fool users. And if a user has already granted unlimited approval to a contract months ago, Rabby cannot retroactively prevent the exploit—the user must still actively revoke it.
Real-world effectiveness: when warnings are seen and when they are ignored
The difference between Etherscan and Rabby Wallet becomes practical when a user is under pressure. Someone notices unusual transactions on their block, realizes they have been targeted, and wants to stop the drain immediately. A user who uses Etherscan must open a new browser tab, navigate to the site, connect their wallet, search through their approval list, identify the malicious contract, and initiate a revocation—all while tokens are being transferred out. This sequence can take several minutes, and by then the damage may be done.
A Rabby Wallet user, by contrast, can open the wallet extension directly, navigate to the approvals section, and revoke a problematic contract without leaving the application. Because Rabby is already integrated with the browser, the revocation can happen faster. More importantly, if the user is in the process of interacting with a new dApp when they grant an approval, Rabby’s simulation and risk warnings appear before the decision is made. This front-loaded protection is more effective than auditing old approvals after the fact.
However, effectiveness also depends on user behavior. Research into real wallet drains shows that many victims were aware of the approval mechanism but either did not check their permissions or did not revoke old approvals because they felt the risk was low. An integrated warning in Rabby Wallet is more visible than an Etherscan dashboard, but it only helps users who understand what the warning means. A user who dismisses warnings or who is distracted during the approval process is vulnerable regardless of the tool.
The data suggests that for prevention—stopping approvals before they are granted—Rabby Wallet is more effective because the warning is synchronous with the decision. For remediation—revoking an approval that has already been granted—Etherscan and Rabby are comparable, though Rabby’s integration may make the process slightly faster. The real world problem is that most users do not perform regular approval audits on either platform until after they have lost money.
Comparing approval revocation across multiple EVM networks
One practical advantage of Rabby Wallet is that it supports multiple EVM-compatible blockchains including Ethereum mainnet, Arbitrum, Optimism, Polygon, and BNB Smart Chain. A user can manage approvals across all these networks from a single wallet interface. Etherscan also covers many of these networks through separate instances (polygonscan.com, arbiscan.io, and so on), but a user must navigate to each instance separately and connect their wallet each time. For users with assets spread across multiple EVM chains, Rabby Wallet’s unified interface is more convenient.
However, this advantage applies only to users who know about the feature. Many users think of Rabby Wallet primarily as a way to interact with dApps and swap tokens, not as a comprehensive approval management tool. Similarly, users who are familiar with Etherscan mainnet may not realize that approval auditing tools exist on other explorers. This is partly a documentation problem: the more powerful tools available, the less likely average users are to know about them. A self-custodial Web3 wallet like Rabby has an opportunity to guide users toward better practices through onboarding and in-app education, but this requires deliberate design and effort.
The bridge feature in Rabby Wallet, which allows users to move assets across multiple EVM networks, further complicates approval management. A user bridging assets to a new chain may grant new approvals on that chain and forget about old approvals on the original chain. A comprehensive audit requires checking the approval history on all relevant networks. Neither Rabby Wallet nor Etherscan automatically consolidates this view; a user must still manually check each chain.
How open source verification strengthens approval security
Rabby Wallet is published as open source code on GitHub, which means users and security researchers can inspect the approval management logic and the risk detection algorithms. This transparency has a specific benefit: a user who is skeptical of the risk warnings can examine the code and understand exactly what conditions trigger an alert. A security researcher can audit the code and report bugs. The community can submit improvements and fixes.
The open source nature of Rabby Wallet also means that the approval detection logic cannot contain hidden exploits or undisclosed risks. If the wallet had a vulnerability in how it handles approvals or revocations, it would be visible to anyone who reviewed the code. Etherscan is also transparent about how it displays approvals because the blockchain itself is transparent, but the backend logic that Etherscan uses to identify malicious contracts is proprietary. A user must trust Etherscan’s flagging system without being able to audit it directly.
However, open source code can create a false sense of security if users do not actually read it. Most users downloading a self-custodial Web3 wallet like Rabby do not verify the source code themselves. They rely on the reputation of the project, the community, and the developers. If the code is open source but users do not review it, the transparency provides security for the broader community and researchers but not necessarily for the individual user.
The critical role of user education in approval security
Both Etherscan and Rabby Wallet can prevent wallet drains, but only if users understand what approvals are and why they matter. A user who grants unlimited approval to a new dApp without understanding the risk will be vulnerable regardless of which tool is available. The most common approval-related losses occur because users did not know about approvals at all, did not realize they had granted them, or did not understand the difference between a revocable approval and a permanent loss of private keys.
Education is therefore the primary defense. A wallet like Rabby has the advantage of being able to teach users through in-app onboarding and contextual warnings. When a user approves a contract for the first time, the wallet can explain what an approval is, what it allows the contract to do, and how to revoke it later. Etherscan, being a passive explorer, has less opportunity to educate users in real-time. A user must visit Etherscan and read its documentation to understand how to use the approvals tool.
The second element of education is recognizing social engineering. Many approval-based wallet drains begin with a phishing email, a fake website, or a scam Discord message that directs users to a malicious contract. A user who understands that approvals are permanent and that every dApp interaction should be scrutinized is more likely to catch the attack. A user who clicks links without checking domain names is vulnerable. Here again, Rabby Wallet can help by warning users about known phishing domains and by displaying the actual domain being interacted with in the transaction simulation.
Which tool prevents wallet drains in practice
The honest answer is that neither Etherscan’s approval dashboard nor Rabby Wallet’s integrated manager can prevent all wallet drains. Both are reactive or delayed: Etherscan reacts after the user has already granted approval, and Rabby Wallet simulates transactions but cannot prevent a user from ignoring the warning. The real prevention happens at the moment of decision: a user who carefully reads a transaction simulation, understands what approval is being requested, and refuses to grant unlimited access to unknown contracts is unlikely to be exploited.
If forced to choose which tool is more effective at preventing actual losses, Rabby Wallet has the structural advantage because its warnings are integrated into the approval flow. A user interacting with a dApp receives a warning about the contract before granting approval. This synchronous warning is more likely to be noticed and heeded than an asynchronous check of Etherscan later. However, Rabby’s advantage depends on the wallet’s risk detection being accurate and comprehensive. If the contract is new and not yet flagged, or if the dApp is a legitimate service that has been compromised, Rabby may not catch it.
For users who want maximum control and transparency, a workflow combining both tools is most effective. Use Rabby Wallet to interact with dApps and benefit from transaction simulation and integrated risk warnings. Use Etherscan or similar tools to audit old approvals and revoke any that are no longer needed or are suspected to be dangerous. Do not rely on either tool exclusively. The rabby wallet can prevent approvals from being granted in the first place, while Etherscan can help clean up old permissions after the fact.
Implementing approval hygiene as an ongoing practice
Preventing wallet drains requires treating token approvals as a permanent maintenance task, not a one-time setup. A user should establish a regular practice: approve contracts only when necessary, grant the minimum amount needed rather than unlimited access, and periodically audit old approvals to revoke those that are no longer needed. This is time-consuming, which is why most users skip it. But the users who maintain approval hygiene are also the users who are least likely to lose funds to approval-based exploits.
Tools like Rabby Wallet can support this practice by making approval management visible and accessible. The wallet can show the user a list of all approvals they have granted, even across multiple networks. The user can sort by date, by token, or by contract and decide which to revoke. The wallet can also provide recommendations, such as revoking approvals to contracts that have been inactive for six months or longer. An open source wallet gives users confidence that these recommendations are not designed to extract fees or manipulate behavior.
The alternative is to use separate service addresses for different purposes. A user with significant holdings might use one address for long-term holds that never interact with dApps, another address for active trading and farming, and a third for testing new services. If the active trading address is compromised through an approval exploit, the impact is limited. This is a more sophisticated approach that requires managing multiple wallets and recovery phrases, but it provides defense in depth that no single tool can match.
Frequently asked questions
Can Rabby Wallet prevent all wallet drains caused by token approvals?
No. Rabby Wallet can warn users before they grant dangerous approvals through transaction simulation and risk detection, which is a strong preventive tool. However, if a user ignores the warning or if the contract is brand new and not yet flagged as malicious, the protection is limited. Additionally, if an approval has already been granted in the past, Rabby can help revoke it, but it cannot retroactively prevent an exploit that has already occurred. Prevention requires user awareness and careful judgment at the moment of approval.
Is Etherscan’s approval management better than a wallet’s built-in approval manager?
They serve different purposes. Etherscan’s approvals dashboard is comprehensive, transparent, and works across all EVM chains without requiring you to install new software. However, it is passive—you must remember to check it regularly. An integrated approval manager in a self-custodial Web3 wallet like Rabby Wallet is more proactive because warnings appear during dApp interactions. Etherscan is better for auditing old approvals, while a wallet is better for preventing new dangerous approvals from being granted.
What is the best way to protect against approval-based wallet drains?
A combination of practices works best: understand what token approvals are, use a wallet with transaction simulation to review permissions before granting them, approve only the minimum amount needed rather than unlimited access, and periodically audit and revoke old approvals using tools like Etherscan or your wallet’s approval manager. Rabby Wallet’s built-in approval features support this workflow, but user awareness and caution are the primary defenses.