The Interview Was the Install

Developers are being handed that tool in job interviews. And the panel it gets plugged into is the same laptop that holds their wallet.

What the agencies found

On September 18, seven agencies in four countries published a joint advisory: Japan's National Police Agency and National Cybersecurity Office, the FBI and the Defense Department's Cyber Crime Center, Australia's ACSC, and Germany's BND and BfV. It covers a North Korean group they call WaterPlum, better known as "Contagious Interview."

The numbers are from Japan's National Police Agency. From around December 2025 through July 2026, the group compromised at least 30,000 PCs in more than 100 countries. It took funds or account credentials from over 7,000 cryptocurrency wallets and moved at least 1.7 billion yen, which the agencies put at $10.71 million, to North Korea. The primary targets, in the advisory's words, were "web designers, engineers, and specialists in cryptocurrency, blockchain, and Web3 technologies." The Register and BleepingComputer carried the same figures.

The NPA and the FBI assess that the group works under the 313 General Bureau of North Korea's Munitions Industry Department. That's their attribution, not mine. What I can speak to is how the attack works, because it's aimed squarely at the people I teach.

How it works

The recruiter looks like an AI, crypto or NFT company. The advisory says the approach comes through social media, job boards, gig platforms and freelance marketplaces. There's a video interview, then a technical step. The candidate is told to download and run something to "complete a coding assignment or troubleshoot an error" with the video call.

The advisory also notes the interviewers used AI face-swapping software, then turned their video off after a few minutes and told the candidate to do the same, blaming the network.

The payloads are named: BeaverTail, InvisibleFerret, OtterCookie, OtterCandy and StoatWaffle, some of them hidden in npm packages. What they're after is listed too: passwords saved in browsers, clipboard contents, keystrokes, screenshots, "private key, seed phrase," and scans of driver's licenses and passports.

The detail that matters

StoatWaffle is the one I'd put in front of every developer who holds crypto. Per the advisory, it uses "blockchain-themed project repositories as decoys," with a malicious VS Code configuration file that runs code "when the folder is opened and trusted by the victim."

Opened and trusted. When VS Code opens a new folder, it asks, in the advisory's wording, "Do you trust the author of the files in this folder?" Answer no and the folder opens in Restricted Mode, which, per Microsoft's documentation, disables or limits AI agents, the terminal, tasks, debugging, workspace settings and extensions. Answer yes and the project's tasks file can run the moment the folder opens.

Most of us click yes without reading it. It's our code, usually. But in this version of the attack, that dialog is the whole security boundary. There's no exploit. The candidate grants permission, and the software does what it was allowed to do.

The coding test isn't a test of you. It's a test of whether you'll say yes.

There's a quieter version of the same trap. Microsoft's documentation says that if you trust a parent folder, every subfolder is trusted, and you won't even see the prompt. If you once trusted the folder where you keep all your repos, anything you clone into it later opens trusted. The advisory warns about exactly this: don't open unknown projects from a path you've already marked as trusted.

What I'd do

I lost 9 bitcoin to security mistakes. None of them looked dangerous at the time. That's the point of this attack, too.

1. Never run a stranger's code on the machine that holds your keys. The advisory says it plainly: don't run untrusted code on a PC "handling cryptocurrency assets or personal data." Use a virtual machine or a separate, clean computer for take-home tests.
2. Answer "No" to the trust prompt for anything you didn't write. Read .vscode/tasks.json in Restricted Mode or another editor before you trust anything.
3. Clone unknown projects somewhere new. Not into a folder you've already trusted.
4. Treat "run this to fix the video call" as the attack. A real employer's meeting software doesn't need a file from the interviewer.
5. If you already ran it, assume your keys are gone. The agencies' guidance: disconnect, assume the wallet data was taken even after the malware is removed, make a new wallet on a separate device, move everything to it, store the new phrase offline, and reset the operating system.

And the standing rule: a recovery phrase doesn't belong on a development machine at all. Not in a browser extension you also use for testing, not in a notes file, not in a screenshot. The machine where you open other people's code is the most exposed computer you own.

Look at the cord before it goes near the panel.

Verify everything, especially the part of the job interview that asks you to trust someone.