blockchains-security-toolkit/advanced_expert/vulnerabilities

smart contract vulnerabilities

initial thoughts

• tx.origin needs to be replaced by msg.sender, otherwise any contract you call can act on your behalf.
• inline assembly should be used only in rare cases.
• unclear semantics: now is alias for block.timestamp not current time; use of low level call, callcode, delegatecall should be avoided whenever possible; use transfer whenever failure of ether transfer should rollback the whole transaction.
• beware of caller contracts: selfdestruct can block calling contracts unexpectedly.
• invocation of local functions via this: never use this to call functions in the same contract, it only consumes more gas than normal call.
• transferring Ether in a for/while/do-while loop should be avoided due to the block gas limit.
• erc20 decimals should have uint8 as return type.

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chapters

• reentrancy
• randomness in ethereum
• code injection via delegatecall
• arithmetic errors
• self_destruct
• ddos attacks
• nonce reuse
• replay attacks

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cool resources

• secureum-mind-map
• defi hacks & exploits
• ethereum smart contract security best practices
• biased nonce sense lattice attacks against weak ECDSA