Malicious code in polymarket-auto-trade (npm)

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-auto-trade targets developers seeking trade-automation tooling. Payload is identical to the rest of the campaign.

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Source: ghsa-malware (836c76164041e544501cf8b1943d449d54823dae387c4809cd3cb0c1ad001dba)

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.