👮
Contract Cops
  • Mastering Ethereum Book
    • What is ethereum?
    • Tokens
    • Oracles
    • Decenralized Applications(DApps)
    • The Ethereum virtual machine
    • Ethereum basics
    • Ethereum clients
    • Cryptography
    • Wallets
    • Transactions
    • Chapter 7 - Smart Contracts & Solidity
    • Side Notes
      • Tokens
      • Smart Contracts and Solidity
  • Cryptography
    • Ethereum Cryptography - Cheatsheet
    • Assymetric vs symmetric cryptography
    • ECDSA vs RSA
    • Elliptic curves and ECDSA
    • Sha-256 Example
    • Sha-256
    • What are the different steps in SHA-256?
  • Ethereum Blocks
    • Block Headers
  • Learning Solidity
    • Storage vs memory
    • Upgradeable contracts
      • Proxy pattern in smart contracts
  • PoS
    • Proof of stake
  • PoW
    • PoW
  • Tokens
    • ERC-1155
    • ERC20
  • Cryptonomics
    • Automated market makers
    • Collateral Tokens
    • Collateralized Stablecoin
    • Fiat currency
    • Liquidity pool
    • Open Position: Meaning and Risk in Trading
    • Slippage
    • Spot price
  • Common Attack Vectors
    • Checking access control
    • Access control issues on critical functions
    • Account Existence Check for low level calls
    • Account Existence Check
    • Common attacks with contract/EOA addresses
    • Arithmetic under/overflow
    • Assert Attack
    • Assert require revert
    • Assert Violation
    • Bad Interface DOS
    • Bad pragma and compiler
    • Block Timestamp Manipulation
    • Bypassing contract check
    • Code With No Effects
    • Code size check vulnerability
    • Constructors with Care
    • Default Visibilities
    • Delegatecall
    • Delegatecall
    • Denial of Service (DoS)
    • DoS with block gas limit
    • Entropy Illusion
    • External contract referencing
    • Flash Loan Attack
    • Floating Point and Precision
    • Function selector abuse
    • Function selector abuse
    • Smart contract gas griefing
    • Hash collision parameters
    • Hash Collisions With Multiple Variable Length Arguments
    • Imprecise arithmetic
    • Improper Array Deletion
    • Incorrect array deletion
    • Incorrect interface
    • Insufficient Gas Griefing
    • Loop through long arrays
    • Message call with hardcoded gas amount
    • Not enough gas for ether transfer
    • Precision Loss in Calculations
    • Oracle Manipulation
    • Public Burn Function
    • Read-only reentrancy
    • Race Conditions/Front Running
    • Reentrancy Attacks
    • Reentrancy
    • Requirement Violation
    • Right-To-Left-Override control character (U+202E)
    • Shadowing State Variables
    • Short Address / Parameter attack
    • Signature Malleability
    • Signature Replay
    • Transaction Order Dependence
    • Tx.Origin Authentication
    • Unchecked CALL Return Values
    • Unexpected ether
    • Uninitialized Storage Pointers
    • Unsafe Ownership Transfer
  • EIP's
    • EIP155
    • EIP55
  • PoW
    • Ethash
    • Scrypt - RFC 7914
  • Questions for self evaluation
    • Questions 23/04/2023 (Nr: 84)
    • Usability guide for questions
  • Frequently asked questions
    • What is the difference between transaction and message?
    • What is the use of a interface or function without implementation?
  • UsefulResources
Powered by GitBook
On this page
  • The Vulnerability
  • Preventative Techniques
  1. Common Attack Vectors

Default Visibilities

PreviousConstructors with CareNextDelegatecall

Last updated 2 years ago

Functions in Solidity have visibility specifiers that dictate how they can be called. The visibility determines whether a function can be called externally by users, by other derived contracts, only internally, or only externally.

The Vulnerability

The default visibility for functions is public, so functions that do not specify their visibility will be callable by external users. The issue arises when developers mistakenly omit visibility specifiers on functions that should be private(or only callable within the contract itself).

Preventative Techniques

It is good practice to always specify the visibility of all functions in a contract, even if they are intentionally public.

Default_visibilities