Signing Malicious Transactions

Why You Should Care About Spoof / Malicious Transactions

Even though the blockchain is immutable and secure by design, the interface — what you see when you sign a transaction — can be manipulated. You may think you are approving one thing (e.g. a swap, or an NFT mint) when in fact you are signing a malicious or a phishing transaction. This is often called “UI spoofing” or “phishing contract” attacks.
Recent incidents are rising. For example, signature-based exploits have led to significant losses in 2025 via phishing flows.
Some scams do not rely on private key theft; they trick you into approving a contract that later drains tokens. Once you sign, blockchain rules make the execution irreversible.

Common Attacks

Attack Type

Description / Risk

UI Spoofing / Phishing Contracts

A dApp or malicious site shows a benign transaction interface but encodes malicious calldata (e.g. unlimited token approvals, fund draining). You see something benign, signs, and get exploited. (cyfrin.io)

Address Poisoning / Spoofed Addresses

A scammer sends tiny amounts from addresses that mimic legitimate ones. You copy the wrong address, sending funds to attacker. (Ledger)

Unrestricted/Unlimited Approvals / Blind Signatures

Granting unlimited permissions to unknown or untrusted contracts gives them ongoing access to your funds or tokens. (netcoins.com)

Malicious or Unaudited Smart Contracts / Unaudited dApps

Interacting with dApps without a public audit or community reputation increases the risk of hidden malicious behavior. (startupdefense.io)

Best Practices

Here’s what you should do to protect yourself.

Always review transaction details before signing: Check recipient address, amounts, allowances, and whether the transaction matches your intent. Use whitelists for addresses in your wallets as much as possible. If transaction text looks unreadable or unclear, do not sign. (BlockSec)
Use hardware wallets (cold wallets) if possible. This ensures the private key never touches the internet or a potentially compromised device. (Ledger)
Prefer minimal permissions / scope-based approvals: Avoid granting unlimited permission; only approve what is strictly required for a given operation. Periodically review and revoke unnecessary approvals. (startupdefense.io)
Segregate assets across multiple wallets: Keep long-term holdings in a “cold / safe” wallet; use a separate “interaction wallet” for risky or experimental dApps. (Ledger)
Avoid suspicious links, bookmark trusted sites, verify URLs — don’t use search results casually; phishing often comes via fake sites or typosquatted domains. (Ledger)
Limit exposure: avoid interacting with unknown or un-audited dApps. Prefer dApps with audit reports, good reputation, and visible community feedback. (startupdefense.io)
Keep your Wallets and Extensions Updated: Wallet app, browser extensions, OS — patching helps prevent exploitation of known vulnerabilities. (onekey.so)

Why You Should Care About Spoof / Malicious Transactions

Common Attacks

Best Practices

Further Reading