How DPRK Hackers Use Cross-Chain Crypto Laundering to Evade Detection

North Korean hackers aren’t just stealing crypto-they’re rewriting the rules of how money moves online. In 2025, a single attack on Bybit drained over $1.5 billion in cryptocurrency, making it the largest crypto heist in history. That’s more than all of North Korea’s crypto thefts in 2023 combined. And this isn’t an anomaly. It’s the new normal.

Why Cross-Chain Laundering Is the New Weapon of Choice

Years ago, hackers used mixing services like Tornado Cash to hide stolen funds. But as regulators cracked down, those tools became too risky. So North Korea’s cyber units, especially the Lazarus Group, switched tactics. Now, they don’t just hide money-they bounce it between blockchains.

Cross-chain bridges are the key. These are platforms designed to let users move assets between networks like Ethereum, Bitcoin, Tron, and Solana. But they’re not built for security. They’re built for speed. And that’s exactly what DPRK hackers exploit.

Here’s how it works: after stealing Ethereum from an exchange, they instantly swap it into TRC-20 tokens on Tron. Then they use the Avalanche Bridge to convert those into Bitcoin. From there, they move it to BitTorrent Chain, then back to Ethereum-all within minutes. Each hop breaks the trail. Each swap adds confusion. By the time analysts catch up, the money has vanished into dozens of addresses across six different chains.

TRM Labs found that Lazarus Group deposited over 9,500 BTC through the Avalanche Bridge alone. That’s not a typo. Nine thousand five hundred Bitcoin. At today’s prices, that’s worth more than $600 million. And they’re not slowing down.

The "Flood the Zone" Strategy

North Korean hackers don’t rely on stealth anymore. They rely on volume.

Nick Carlsen, a former FBI cyber expert and now lead analyst at TRM Labs, calls it "flood the zone." Instead of trying to hide one large transaction, they send hundreds of tiny ones at once-across multiple bridges, exchanges, and blockchains. It’s like throwing a handful of sand into a hurricane. No one can track every grain.

In the Bybit breach alone, investigators traced over 1,200 separate cross-chain swaps in the first 72 hours. The hackers used automated scripts to run these transactions nonstop. They didn’t wait for confirmation. They didn’t care if a transaction failed. They just kept sending. And because exchanges and analysts are overwhelmed, many of these transfers slip through.

This isn’t just clever. It’s strategic. North Korea knows that law enforcement can trace one big transfer. But when you’re dealing with 500 small ones spread across five networks? It’s nearly impossible.

From Exchanges to People

The targets have changed, too.

In 2023, most attacks hit centralized exchanges-Bybit, CoinEx, Stake.com. But in 2025, hackers are going after individuals. High-net-worth crypto holders. Company executives. Even crypto influencers.

Why? Because their security is weaker. Most people don’t use hardware wallets. They store keys on phones or laptops. Hackers don’t need to break into a billion-dollar exchange. They just need to trick one person into clicking a fake job offer or downloading a malicious app.

Elliptic found that 70% of new crypto thefts in 2025 started with phishing emails, fake social media profiles, or fraudulent NFT giveaways. Once they get a private key, they drain the wallet and start the same cross-chain dance.

The shift from technical exploits to social engineering means anyone with crypto is now a target. Not just institutions. Not just exchanges. You.

How the Money Gets Cleaned (And Why It Stays Hidden)

After the chain-hopping, the money doesn’t just vanish. It sits.

TRM Labs noticed something unusual: most of the Bitcoin converted from stolen Ethereum doesn’t get sold right away. Instead, it sits in cold storage wallets for weeks or months. Why?

Because cashing out now would trigger red flags. Exchanges are watching. Regulators are alert. So the hackers wait. They use over-the-counter (OTC) desks-private, unregulated trading rooms where large amounts of crypto are moved without public records. These OTC desks are often based in jurisdictions with no crypto reporting rules. Some are linked to shell companies in the UAE, Hong Kong, or Southeast Asia.

They also create fake tokens. Not Bitcoin or Ethereum. New, obscure tokens issued on tiny blockchains with no real users. They swap stolen funds into these tokens, move them around, then swap them back into Bitcoin or USDT. The token itself has no value-but the trail it leaves is meaningless to most analysts.

And then there’s the refund trick. Hackers send stolen funds to a wallet. Then they send a tiny amount back to the original address as a "refund." That refund address becomes the new starting point for tracing. But the real money? It’s already gone.

Why This Matters Beyond Crypto

This isn’t just about stolen coins. It’s about nuclear weapons.

A 2024 UN report confirmed what intelligence agencies have suspected for years: North Korea’s missile program, its nuclear warheads, its long-range rockets-they’re funded by crypto theft. A senior Biden administration official said in 2024 that nearly half of North Korea’s foreign currency income comes from cybercrime.

The $2 billion stolen in 2025? That’s enough to buy hundreds of missiles. Or fund a new submarine program. Or pay for uranium enrichment.

The Wilson Center calls it "a matter of global security." When a regime under international sanctions can raise billions in minutes through a few lines of code, the rules of global finance change. And so do the risks.

How Analysts Are Fighting Back

It’s not all one-sided. Blockchain analytics firms are upgrading fast.

In 2019, TRM Labs launched TRM Forensics-the first tool that could trace funds across multiple chains. In 2022, they released TRM Phoenix, which automatically tracks asset movement through bridges. Today, these tools can follow a dollar from Ethereum to Tron to Bitcoin, even if it’s been swapped five times.

CoinDesk reported that in the Bybit case, 12 different blockchain firms worked together with the FBI and Europol to freeze $380 million in stolen assets. That’s unprecedented collaboration.

But it’s a race. Every time analysts improve, North Korea adapts. They now target newer, less-monitored chains like Klaytn, Celo, and Polygon zkEVM. They use decentralized protocols that don’t require KYC. They exploit gaps in analytics coverage.

The bottom line? The tools are getting better. But so are the hackers.

What You Can Do

If you hold crypto, here’s what matters:

• Use a hardware wallet. Never store private keys on your phone or computer.
• Never click links from strangers. Fake job offers, NFT airdrops, and "free ETH" scams are the top entry points.
• Enable 2FA on every exchange. Use an authenticator app, not SMS.
• Monitor your wallet activity. If you see an unfamiliar transaction, freeze your assets and report it immediately.

Most importantly: understand that your security isn’t just about technology. It’s about behavior. The weakest link isn’t the blockchain. It’s you.

The Arms Race Isn’t Over

North Korea’s crypto thefts aren’t slowing down. They’re accelerating. The scale, speed, and sophistication of cross-chain laundering are growing faster than defenses can keep up.

But the tide can turn-if the world treats this like the national security threat it is. Not just a crypto problem. Not just a financial crime. A direct threat to global stability.

The next heist could be bigger. The next laundering method, even harder to trace.

The question isn’t whether another $1 billion attack will happen.

It’s when.