Access Control

Access control detection

When this applies

Any state-mutating function. In particular:

• Functions modifying balances, totalSupply, allowances, prices, fees
• setOwner, transferOwnership, grantRole, setAdmin, setMinter
• Upgrade pathways: upgradeTo, _authorizeUpgrade, proxy admins
• Pause/unpause, emergency-withdraw, sweep, recoverERC20
• Initializers (initialize, __Init, _init)
• Functions guarded only by msg.sender == tx.origin or address checks against a single static value
• Bridges, governors, vaults, anything with treasury

Detection patterns

Missing modifier (CRITICAL)

function mint(address to, uint256 amount) external {
    _mint(to, amount);   // ← anyone can mint
}

Wrong role check (HIGH)

function setFee(uint256 fee) external {
    require(msg.sender == owner || hasRole(USER, msg.sender));   // ← USER role can set fee
    fee_ = fee;
}

Initializer left public (CRITICAL)

function initialize(address admin) public {     // ← no initializer guard, anyone can re-init
    _grantRole(DEFAULT_ADMIN_ROLE, admin);
}

See also: [[initialization]]

tx.origin auth (HIGH)

require(tx.origin == owner);   // ← phishable via intermediate contract

Public privileged getter masking setter

Sometimes a setter is internal but a public wrapper exists with weak checks. Search for "alternate paths" to the same state slot.

Role admin self-grant (HIGH)

DEFAULT_ADMIN_ROLE can grant itself any role. If the admin is an EOA, a single key compromises everything. Look for renounceable admin patterns or multi-sig requirements.

selfdestruct reachable without ownership check (CRITICAL — but see [[selfdestruct-eip6780]])

Sweep / recoverERC20 with no asset allowlist (MEDIUM-HIGH)

function rescue(IERC20 token) external onlyOwner {
    token.transfer(owner, token.balanceOf(address(this)));  // ← sweeps any token incl. user deposits
}

Critical if it can sweep user deposits, Medium if only stuck airdrops.

Severity rubric

| Pattern | Severity | |---|---| | Privileged mint/burn with no auth | Critical | | Public initialize on a deployed proxy | Critical | | Owner sweep that includes user deposits | Critical | | Wrong role guards a sensitive op | High | | tx.origin auth | High | | Centralized single-key admin with no timelock | High (see [[centralization-risk]]) | | Renounced ownership but admin role retained | Medium | | Missing zero-address check on role grant | Low |

Remediation patterns

• Use OwnableUpgradeable / AccessControlUpgradeable from OZ — never roll your own.
• For each function: state the one role that should call it as a comment, then add the matching modifier.
• Initializers: _disableInitializers() in the constructor, initializer modifier on init.
• Multi-sig + timelock on DEFAULT_ADMIN_ROLE. Document the timelock duration.
• Two-step ownership transfer (Ownable2Step) to prevent locking out the contract.
• For sweeps: explicit allowlist of recoverable tokens, or denylist user-deposit tokens.

False-positive notes

• Internal functions called only from properly-guarded externals are fine — verify call sites.
• A function may look unguarded but its only side-effect is emitting an event — Info, not High.
• "Permissionless" by design (e.g. claim() for caller) is fine — verify intent against the spec.

Related

• [[initialization]] — initializer-specific access control
• [[centralization-risk]] — admin-power audit
• [[delegatecall-risks]] — proxy upgrade authorization

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: omermaksutii
• Source: omermaksutii/RugProof
• License: MIT
• Homepage: https://omermaksutii.github.io/RugProof

Install and usage instructions live in the source repository linked above.