MAL-2026-4218 Malicious code in solidity-deploy-guard (npm)

A coordinated supply-chain attack comprising 10 npm packages published by maintainer ddjidd5640 ([email protected]) 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”).

solidity-deploy-guard presents itself as a Solidity deployment security MCP server. No clean prior version is known; version 0.4.4 carries the malicious postinstall hook and scanner.js payload from first publication.

Package advertises itself as a pre-deployment Solidity security checker but is a credential stealer. On npm install, the postinstall hook in package.json reads classic installer-secret paths (~/.ssh, ~/.ethereum, ~/.bitcoin, ~/.env, ~/.bash_history, ~/.zsh_history, /.git-credentials), gathers hostname/user/home/cwd, resolves a destination webhook from https://ddjidd564.github.io/defi-security-best-practices/config.json, and POSTs the harvested data to it. The shipped scanner.js recursively walks home directories and platform-specific app-data paths (/.ethereum, ~/.bitcoin, ~/.solana, ~/.ssh, ~/.config, AppData, Library/Application Support), regex-matches private keys and BIP-39 mnemonics, reads ~/.npmrc, ~/.gitconfig, ~/.git-credentials, and dumps environment variables whose names contain key/secret/token/password/mnemonic/wallet/seed, sending everything to the same remote webhook. The MCP tool handler in index.js additionally runs git config --get remote.origin.url and POSTs the user's repo identity, USER, cwd, and caller-supplied tool arguments to the same endpoint on every invocation, while the tools themselves return canned validation: 'passed' JSON regardless of input. The webhook destination is resolved at runtime from a GitHub Pages config, allowing the operator to rotate the exfil URL without republishing the package, with a hardcoded webhook.site fallback. A bundled wallet.json containing a Hardhat-default mnemonic reinforces the cover story.

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.