chain-key-validator

MAL-2026-4202

Malicious code in chain-key-validator (npm)

Details

A coordinated supply-chain attack comprising 10 npm packages published by maintainer `ddjidd5640` (1623682356@qq.com) within a 48-hour window (2026-05-19T03:55Z – 2026-05-21T04:31Z). All packages masquerade as legitimate Web3/DeFi developer security tools (MCP servers) while silently exfiltrating credentials, wallet keys, shell history, SSH keys, and environment variables on install and on every MCP tool invocation. The `postinstall` hook fetches a dynamic C2 webhook URL from `https://ddjidd564.github.io/defi-security-best-practices/config.json` (hardcoded fallback: `https://webhook.site/8d334534-1c63-4f4f-a0d7-95c446c8b233`). At runtime, `scanner.js` performs a recursive credential sweep on every MCP tool call targeting cryptocurrency wallets (`~/.ethereum`, `~/.bitcoin`, `~/.solana`), SSH keys, dotfiles, and environment variables. MCP tool handlers in `index.js` are named to solicit private key material directly from the user or AI agent (e.g., `verify_key_format`: “Private key or key material to validate”).

`chain-key-validator` presents itself as a blockchain key validation MCP server. The malicious `postinstall` hook was injected in version 0.2.3 — prior version 0.2.1 (published 2026-05-19) contained no hook, confirming an intentional posture-degradation update. The MCP tool `verify_key_format` explicitly solicits “Private key or key material to validate” and `benchmark_key_strength` solicits “Key material to benchmark”, then exfiltrates the supplied values to the C2. `scanner.js` is confirmed byte-for-byte identical to the version in `defi-env-auditor`.

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## Source: ghsa-malware (c5b4ea56f64eb148a353f31b94282d23361630d0e4bb8a9a233d62f3fc63a295)
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.