MetaMask has released Added Protection, a wallet feature designed to stop “red pill” attacks that show one result during transaction simulation and produce another after the user signs. With the feature enabled, the executed transaction must match the preview or revert.
How preview deception works
Wallets commonly simulate a proposed transaction before asking for approval. The simulation estimates balance changes and contract actions so the user can see an expected outcome. A hostile contract can detect the simulation environment, return a harmless result for the preview and execute different logic on-chain.
That gap weakens the preview as a safety control. A user may approve what appears to be a small swap or incoming payment while the live call attempts to transfer valuable tokens or permissions.
MetaMask binds execution to the preview
According to MetaMask’s product announcement, Added Protection simulates the transaction and places the expected result into the transaction as an enforceable condition. If live execution differs from that result, the transaction fails and the wallet’s assets do not move.
A reverted transaction can still consume network gas. MetaMask does not charge a separate fee for the feature or for the failed attempt. The protection targets manipulated execution outcomes; it cannot prevent ordinary price movement, slippage within accepted limits or every form of malicious approval.
Where the feature is available
Added Protection launched as an on-by-default option in MetaMask extension version 13.45. It covers the 13 EVM networks where MetaMask supports smart accounts through EIP-7702. Mobile support is planned to follow, and extension users can disable the protection from the confirmation screen.
The implementation makes the preview more than an informational warning. It also introduces a dependency on accurate simulation and the wallet’s comparison of expected and actual effects. Users should keep the extension current and confirm that the option remains active on supported networks.
What users should still check
A matching preview can still describe a bad transaction. Read token amounts, recipients and permission changes before signing. Avoid unlimited allowances when a smaller approval is sufficient, and do not assume a familiar interface guarantees a safe contract address.
Phishing sites can also request signatures rather than transactions, imitate wallet dialogs or persuade users to disable protection. Added Protection narrows one attack path; it does not replace address verification, account separation and careful permission management.
A practical containment strategy
Use a separate wallet with limited funds for unfamiliar applications. Keep reserves away from routine contract interactions, and revoke approvals after they are no longer needed. For a large or unusual transaction, compare the contract address with the project’s official documentation before accepting the preview.
The new control is most useful when it stays one layer in a wider defense. Its specific promise is testable: the transaction shown by the simulation should be the transaction that executes, or the call should fail.
Sources & further reading
- BlockchainReporter — Adapted from: MetaMask Launches Added Protection to Stop Red Pill Attacks
- MetaMask — Primary announcement: Added Protection prevents red pill attacks