Can a Contract’s Fallback Function Intentionally Consume More than 2,300 Gas?
Yes, a contract's fallback function can be programmed to intentionally consume more than 2,300 gas by including gas-intensive operations, such as writing to storage or executing a loop. If such a contract receives Ether via transfer or send , the transaction will revert due to an out-of-gas error in the fallback function.
This is a potential denial-of-service vector for legitimate transfers.
Glossar
Writing to Storage
Operations ⎊ Writing to Storage involves the operation of permanently recording data into the contract's persistent storage slots on the blockchain, an action that is significantly more expensive in terms of gas than temporary memory operations.
Fallback Function
Contingency ⎊ A fallback function within cryptocurrency derivatives serves as a pre-defined operational protocol activated when primary system components, such as oracles or clearinghouses, experience disruptions or fail to deliver expected data or execution.