Missing contract-existence checks before low-level calls

• Severity: Low

• Confidence: High

Description

Low-level calls return success if there is no code present at the specified address. In addition to the zero-address checks, add a check to verify that <address>.code.length > 0 or use the extcodesize assembly operation to verify the presence of contract code at the specified address. Both these methods ensure the existence of a contract before making a low-level call.