How to Use Browser Extensions to Detect Scam Transactions and Protect Your Crypto
In this lesson, we’ll look at three browser extensions that can protect your assets by showing exactly what a transaction will do before you sign it.
These tools act as a visual firewall between you and scammers — clearly displaying whether a transaction will spend your tokens, drain your wallet, or execute a legitimate action.
Recap: The Typical Scam Setup
In the previous lesson, I showed how a phishing site requested permission to withdraw assets under the pretext of a “free airdrop.”
When I connected my wallet, the site pushed a transaction asking to increase the allowance for my tokens — effectively granting the attacker permission to spend everything.
MetaMask displayed a standard confirmation dialog, which looks harmless to newcomers.
If I had signed it, I would have lost all tokens within seconds.
So, I disconnected from the site — and now I’ll show how the same transaction looks with protective extensions enabled.
Why Extensions Matter
Connecting a wallet to a website is usually safe.
The real danger begins when you sign a transaction.
These browser extensions analyze the transaction in real time and display:
- What assets are being approved or spent.
- Whether you’re granting unlimited spending rights.
- If the contract or website looks suspicious.
Each extension works similarly, differing mostly by interface and design. You can install whichever suits you best.
Extension #1 — Standalone Browser Protection
I install the first extension and pin it to my browser toolbar.
The setup is simple — no extra configuration required.
Then I return to the same phishing site that previously pushed the fake airdrop transaction.
I click “Get Rewards,” connect MetaMask, and wait.
Immediately, the extension detects the malicious operation:
Warning: This transaction will spend all your tokens.
This is exactly what we need — a clear alert that the site is attempting to withdraw everything.
I cancel the transaction.
The site tries to push it again — I disconnect (Disconnect).
✅ Result: Scam avoided before signature.
Extension #2 — Legacy Extension with Scanner
The next extension I test is a popular tool I mentioned earlier.
While it’s no longer actively maintained (support ends after June), it still works for now.
It installs directly into Chrome and supports major networks like:
- Ethereum
- Polygon
- Arbitrum
(more are being added)
It includes a scanner that checks your wallet for existing risky approvals.
I click “Scan,” connect my wallet, and it confirms:
“No dangerous approvals found.”
However, when I revisit the phishing site, the warning doesn’t appear — likely because this Chrome profile doesn’t have my active MetaMask connection.
If installed in the same browser profile as MetaMask, it works as intended.
✅ Result: Useful scanner + partial integration, but limited support and maintenance.
Extension #3 — Direct MetaMask Integration
This option is installed inside MetaMask itself as an add-on.
It integrates directly into the transaction confirmation flow.
I add the plugin, enable it, and refresh the page.
Once connected, I initiate the same fake airdrop transaction.
The plugin shows:
- A clear breakdown of the requested token approvals.
- Which assets are at risk.
- Domain analysis, including the site’s creation date (e.g., “domain registered 3 days ago”).
- A risk indicator warning that the transaction allows spending of all wallet assets.
I click Reject.
✅ Result: Seamless integration and detailed insights directly in MetaMask.
⚠️ Limitation: Works only with MetaMask and selected networks.
Testing with a Legitimate Transaction
Now, let’s compare the extensions’ behavior with a normal swap on a decentralized exchange aggregator.
Example:
- I swap 5 tokens for 5 others.
- MetaMask asks for permission to use 5 tokens.
- I approve the transaction.
The extension doesn’t trigger a warning because:
- It’s a standard swap.
- Inputs and outputs are balanced.
- No suspicious unlimited approvals appear.
✅ Result: Everything looks fine. The extension correctly detects this as a legitimate transaction.
Alternative: Wallets with Built-In Transaction Inspection
If you prefer not to use browser extensions, some wallets (like Rabby Wallet) already have this functionality built in.
They show:
- Which assets are sent or received.
- What approvals are being granted.
- Whether the transaction affects your current balance.
I cover Rabby Wallet in detail in the “Crypto Wallets” module — it’s an excellent option for users who want integrated protection.
Key Takeaways
| Feature | Browser Extensions | Built-In Wallets |
|---|---|---|
| Installation | Separate browser add-on | Already included |
| Risk Warnings | Yes, visual alerts | Yes, integrated |
| Network Support | Varies per extension | Varies per wallet |
| Ease of Use | Simple setup | Even simpler |
| Ideal For | MetaMask users | Rabby or advanced wallets |
Security Rules Recap
- Never sign transactions on unknown sites.
- Always disconnect from suspicious websites.
- Use extensions that display what a transaction actually does.
- Check allowances regularly and revoke excessive approvals.
- Avoid installing unsupported or outdated plugins.
- Keep MetaMask and browser updated.
- Bookmark official sites and ignore links from emails or ads.
What’s Next
In the next lesson, I’ll show my personal wallet setup — how I use multiple wallets, manage mnemonic phrases, and separate operational funds from long-term storage.
You’ll see how professional-level wallet management looks in practice.
These materials are created for educational purposes only and do not constitute financial advice.