Most Common Crypto Attack Vectors and How to Protect Your Funds
In this lesson, we’ll examine the most common attack vectors that target users’ crypto assets — in other words, your money.
As mentioned in previous lessons, 99% of all losses occur due to user mistakes, not due to wallet vulnerabilities.
Only about 1% of incidents are caused by technical bugs, and even that is usually preventable by choosing well-audited wallets from trusted developers (like MetaMask).
The good news?
You have full control over the remaining 99% — your own security behavior.
Main Attack Target: Your Mnemonic Phrase and Private Keys
Attackers almost always focus on one goal — obtaining your mnemonic phrase or private key (which are essentially the same thing).
The two most common paths they use:
- Phishing websites that ask you to enter your phrase to claim fake rewards or fix fake issues.
- Fake transaction signatures, where you’re tricked into approving a malicious transaction directly from your wallet.
Example #1 — Fake Site Transaction Signing
Here’s a real-world scenario I encountered.
Step-by-Step of the Scam:
- A suspicious token appeared in my wallet — called something like “Free Token”.
- It came with a message and a link claiming I “won a reward.”
- The site asked me to connect my wallet (which is harmless).
- Then it prompted me to sign a transaction to “receive the reward.”
That signature was actually a permission for the attacker to withdraw my tokens.
If I had signed, they would have emptied my wallet in seconds.
How It Works
- The site automatically scans your balances once connected.
- It builds a malicious “approval” transaction giving itself spending rights.
- Once signed, your tokens are gone.
✅ Protection:
- Never sign transactions on unknown sites.
- Always verify domains before connecting your wallet.
- If in doubt, open MetaMask → Settings → Connections → Revoke access for suspicious sites.
Example #2 — Fake Token Airdrops and “Support” Messages
Attackers send you fake tokens or contact you pretending to be support staff.
They’ll claim you must visit a site or “verify” your wallet to receive help.
You’re then asked to:
- Enter your mnemonic phrase, or
- Sign a fake transaction “for confirmation.”
✅ Rule:
Legitimate support teams never ask for your mnemonic phrase or signatures.
Advanced Scam Variants
1. Fake “Claim” or “Bonus” Pages
You click a fake notification like “You won 5,000 tokens!”, connect your wallet, and are asked to sign a transaction — usually an unlimited spending approval.
Once signed, the attacker drains your balance.
2. Phishing via Search Engines
Fake ads often appear above real search results for wallets or exchanges (e.g., “MetaMask official site”).
Once you enter your mnemonic phrase, all funds are stolen.
3. Social Engineering
Attackers approach you on Discord, Telegram, or Twitter pretending to:
- Offer help.
- Be an official support account.
- Or even show personal interest.
Eventually, they’ll ask you to sign something or share your phrase.
✅ Rule:
If anyone — anywhere — asks for your mnemonic phrase, it’s a scam.
Browser Extensions for Extra Protection
Certain browser extensions (anti-phishing or transaction preview tools) can visualize what will happen to your funds before you sign.
They:
- Show exactly which tokens you’re granting access to.
- Highlight risky transactions.
- Warn if you’re interacting with a known scam contract.
MetaMask already includes partial protection, but you can enhance it with external tools that display balance changes pre-signature.
Address Replacement Attacks
If your device is infected with malware, it can replace copied wallet addresses in your clipboard.
You think you pasted your friend’s address, but the scammer’s address is substituted.
✅ How to avoid it:
- Always double-check the first and last 5 characters of every address.
- Use a dedicated crypto device that’s not used for browsing, gaming, or downloading files.
- Keep your operating system clean — Linux or macOS are safer than Windows.
Two Main Attack Vectors — Everything Else Is Just a Variation
All scams ultimately revolve around these two mechanisms:
- Obtaining your mnemonic phrase.
- Tricking you into signing a malicious transaction.
Every attack — no matter how creative — is just a variation of these core principles.
Core Protection Rules
- Never enter your mnemonic phrase anywhere except in your official wallet app.
- Never sign transactions on suspicious or unknown websites.
- Avoid “easy money” traps — there are no free airdrops or giveaways requiring wallet actions.
- Bookmark official sites and avoid clicking links from emails or search ads.
- Use a separate device for crypto operations — isolated from casual browsing.
- Store your mnemonic phrase offline, on paper only.
- Revoke site access in your wallet periodically.
By following these seven rules, you eliminate nearly every practical threat.
If in Doubt — Ask
If something seems suspicious, stop and ask.
You can always check with experienced members in our Discord community before taking any action.
Nobody will judge you for asking — but everyone will regret a mistake that costs them their savings.
Summary
| Attack Vector | Description | Protection |
|---|---|---|
| Phishing Sites | Fake pages asking for your mnemonic | Only use official wallet links |
| Fake Tokens | “Free” tokens leading to fake sites | Ignore them; never sign or claim |
| Fake Support | Scammers posing as help agents | Real support never asks for seed phrases |
| Fake Approvals | Signing unlimited spending permissions | Review transaction details carefully |
| Address Replacement | Clipboard hijacking malware | Double-check address characters |
| Social Engineering | Personal messages with fake help | Don’t trust unsolicited contacts |
In the next lesson, we’ll explore browser security extensions that display transaction effects before you sign — showing how the fake transaction I almost signed would look once these tools are installed.
These materials are created for educational purposes only and do not constitute financial advice.