How a Simple Copy-Paste Error Cost One User 140 ETH: The Hidden Dangers of Address Poisoning

Blockchain security platform monitoring systems, including crypto sniffer tools, recently flagged a concerning incident where an Ethereum holder fell victim to address poisoning—losing a substantial amount in the process.

The Attack: A Costly Mistake

One user accidentally transferred 140 ETH (approximately $636,559 at current market rates) by copying what appeared to be a legitimate wallet address from their transaction history. However, the address was forged by attackers exploiting a technique known as address poisoning. At the time of the incident, Ethereum was trading around these levels, making the loss particularly significant for the victim.

How Address Poisoning Works

The attack mechanism is deceptively simple yet highly effective. Malicious actors deploy small transactions—often dust transfers or zero-value transactions—to target wallets. This tactic serves a specific purpose: to populate the victim’s transaction history with lookalike addresses that closely mimic the user’s frequently accessed wallets.

When users routinely copy and paste addresses from their history without verifying the full wallet address, they become vulnerable to this trick. The forged addresses are intentionally designed to be nearly identical to legitimate ones, just different enough to redirect funds to the attacker’s wallet instead.

Why This Attack Succeeds

The success of address poisoning lies in human error combined with convenience. Most users rely on copy-paste functionality to avoid manual address entry mistakes. By seeding transaction history with convincing duplicates, attackers exploit this habitual behavior. The victim likely trusted their own transaction history as a secure reference point—a reasonable assumption that attackers deliberately undermined.

Protecting Against Address Poisoning

Users should adopt several protective measures: always verify the full wallet address character-by-character before confirming large transfers, enable address whitelisting features if available, and consider using address verification tools or browser extensions. Double-checking the first and last few characters of addresses provides an additional layer of protection, as most poisoned addresses differ only in the middle sections.

This incident serves as a stark reminder that even tech-savvy users remain vulnerable to sophisticated social engineering tactics in the crypto space.