Flow

Summary

Inadequate specification of visibility for functions in the SablierFlow.sol contract can lead to unintended access to sensitive functions, potentially allowing malicious actors to interact with the contract in unintended ways.

Finding Description

The contract contains several functions that do not explicitly declare their visibility as internal, private, or public. Without clear visibility specifiers, there is a risk that external contracts or users may call these functions unintentionally. This could lead to unauthorized state changes, security breaches, or the mismanagement of funds. Proper visibility specifiers are essential in Solidity to ensure that only intended callers can access certain functions.

This vulnerability breaks the security guarantees provided by access control mechanisms in the contract, allowing for unauthorized function calls that could manipulate internal state or perform critical operations without appropriate permissions.

Malicious Input Propagation

For example, if a function designed for internal management of state variables is publicly accessible, a malicious user or contract could invoke it, leading to unintended consequences. This could include changing balances, triggering transfers, or altering crucial parameters of the contract.

Vulnerability Details

The affected functions should explicitly define their visibility:

• Functions intended to be called only from within the contract or derived contracts should use the internal keyword.

• Functions that should only be accessible from within the contract itself should be marked as private.

• Functions meant for external interaction should clearly be declared as public.

Impact

The impact of this vulnerability is categorized as Medium Severity. While it may not lead to immediate catastrophic failure of the contract, the potential for unauthorized access could compromise the integrity of the contract's state and logic. Proper access control is a foundational aspect of smart contract security, and neglecting visibility specifiers increases the attack surface of the contract.

Proof of Concept