One stolen npm token, a hundred poisoned dapps: inside the Ledger Connect Kit attack

On December 14, 2023, thousands of people who never touched a Ledger device were still put at risk by a Ledger product. The reason was a poisoned software library — @ledgerhq/connect-kit — that quietly loaded a wallet drainer into the front-ends of popular DeFi apps.

Connect Kit is the JavaScript glue that lets web3 dapps talk to Ledger hardware wallets. Because dapps pull it from a CDN and run it directly in the browser, a single tampered version reaches every site that loads it. That is exactly what happened.

Per Ledger's own Security Incident Report, the root cause was mundane and preventable. A former Ledger employee was phished, and their NPMJS account was still active after they had left. Despite two-factor authentication, the attacker used a session token or API key that had never been revoked during offboarding — an access credential that should have died with the job.

With that access, the attacker published malicious Connect Kit versions 1.1.5, 1.1.6 and 1.1.7. Each carried a wallet drainer built on Angel Drainer, a 'drainer-as-a-service' that, according to SlowMist's MistTrack analysis, splits stolen funds roughly 85% to the operator and 15% to Angel Drainer itself.

One library, a hundred front doors

The payload did not break wallets so much as trick their owners. It threw up fake wallet-connection and signing pop-ups — routed through a rogue WalletConnect project — that asked users to approve transactions quietly redirecting assets to attacker addresses.

The blast radius was wide because the dependency was popular. Analyses from SlowMist and Blockaid name SushiSwap, Zapper, Revoke.cash, Kyber Network, hey.xyz (Lens), MetalSwap and Harvest Finance among the affected sites, with more than 100 front-ends touched. Crucially, you did not need to own a Ledger to be hit — merely visiting a poisoned site and signing was enough.

The losses were smaller than the reach suggests. MistTrack put the theft at at least ~$600,000, with some outlets citing figures up to ~$680,000 — a reminder that a supply-chain compromise's damage is capped mostly by how fast defenders move.

A fast takedown, a slow-burning lesson

Ledger moved quickly. The company says it became aware around 1:45 PM CET, deployed a fix within roughly 40 minutes, and shipped a clean version 1.1.8. The malicious file was live for about five hours — prolonged by CDN caching — but the active-draining window was under two hours.

Several teams, including Sushi and Revoke.cash, disabled their interfaces once alerted. Tether froze the stolen USDT after Ledger reported the attacker addresses, and Ledger said on December 20, 2023 that it would reimburse affected users, reportedly making victims whole through the end of February 2024.

The durable lesson is about blind signing. The drainer worked because users approved transactions they could not actually read — a wall of hex that a hardware wallet cannot make legible on its own. Ledger itself said it would push 'clear signing' over blind signing, so that what you confirm on the device screen matches what you think you are doing.

Protect yourself and your builds

• Read what you sign. Prefer wallets and devices that show human-readable transaction details ('clear signing'), and treat any request to blind-sign a raw hex payload as a stop sign.
• Audit approvals regularly. Use a trusted tool to review and revoke token allowances; a drainer's power usually comes from an approval you granted, not your seed phrase.
• Slow down on unexpected pop-ups. A connection or signing prompt you did not initiate — especially one routed through an unfamiliar WalletConnect session — is a red flag.
• Builders: pin your dependencies. Lock exact versions and verify integrity hashes (lockfiles, subresource integrity) rather than auto-pulling 'latest' from a CDN.
• Builders: close the offboarding gap. Revoke every token, API key and package-registry session when someone leaves; 2FA does not help if a live credential survives the exit.

None of this requires owning a Ledger to matter. The Connect Kit attack is a template — one weak credential, one shared library, many victims — and the defenses are the same whether you are signing a transaction or shipping code that asks others to.

— Sources: [Ledger Security Incident Report](https://www.ledger.com/blog/security-incident-report) · [BleepingComputer](https://www.bleepingcomputer.com/news/security/ledger-dapp-supply-chain-attack-steals-600k-from-crypto-wallets/) · [SlowMist / MistTrack](https://slowmist.medium.com/supply-chain-attack-on-ledger-connect-kit-analyzing-the-impact-and-preventive-measures-1005e39422fd) · [Blockaid](https://www.blockaid.io/blog/attack-report-ledger-connect-kit)