EvilReflex: Exploiting the approveAndCallcode Vulnerability in Block 18 (18T) ERC20 Token

CVE-2018-12703 · MEDIUM Severity

AV:N/AC:L/AU:N/C:N/I:P/A:N

The approveAndCallcode function of a smart contract implementation for Block 18 (18T), an tradable Ethereum ERC20 token, allows attackers to steal assets (e.g., transfer the contract's balances into their account) because the callcode (i.e., _spender.call(_extraData)) is not verified, aka the "evilReflex" issue. NOTE: a PeckShield disclosure states "some researchers have independently discussed the mechanism of such vulnerability."

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