Smart Contract Safety: How to Verify Before You Interact

What steps should I take to verify a smart contract before interacting with it?

In the decentralized world of blockchain, smart contracts play a crucial role in automating and securing transactions. However, interacting with a malicious or poorly designed contract can lead to significant financial loss or compromised security. To protect yourself, it’s essential to verify the contract before any interaction. Here are the main steps to follow:

1. Check Contract Verification on Etherscan

The first step in verifying a smart contract is to ensure it’s been verified on Etherscan. Verified contracts have their source code publicly available, which allows you to review and analyze the code. Here’s how to check:

Go to the contract’s address on Etherscan.

Look for the “Contract” tab. If the contract is verified, you will see the source code along with a green checkmark, as below:

Verification ensures transparency, allowing users to scrutinize the contract for vulnerabilities or malicious logic.

2. Determine If the Contract Is a Proxy

Many projects use proxy contracts to allow upgrades without changing the contract address. While proxies offer flexibility, they introduce risks if not managed correctly. If the contract is a proxy, it’s essential to check the following:

• Upgradeability: A proxy contract’s owner can upgrade the implementation contract, potentially introducing malicious code at any time.




• Ownership Details: Identify who controls the contract (via owner or admin roles). This information is crucial as an irresponsible or malicious owner could compromise the contract.

3. Inspect the Implementation Contract

If the contract is a proxy, you need to verify the underlying implementation logic. Follow these steps:

Navigate to the Implementation Address:

On Etherscan, go to the “Read Contract” section of the proxy contract.

Locate and click on the implementation or equivalent function, which returns the address of the implementation contract.

4. Review the Implementation Code:

Once you have the implementation address, inspect its contract code.

• Check for potential backdoors, such as functions that allow unauthorized access or withdrawals.


• Look for suspicious functionalities that could compromise user funds or data.

5. Key Points to Watch Out For:

• Hidden Backdoors: Ensure no functions allow arbitrary changes to critical parameters or access to funds.


• Emergency Withdrawals: Be cautious of any emergency functions that might allow the owner to drain funds.


• Unverified Contracts: If the contract or its implementation is unverified, proceed with extreme caution.

By following these steps, you can significantly reduce the risks associated with interacting with smart contracts. Always prioritize security and take the time to fully understand the code you’re trusting with your assets.

The examples from etherscan are taken from a deployed bulk sender contracts, open sourced here: