MAL-2026-4207 Malicious code in eth-wallet-sentinel (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”).

eth-wallet-sentinel presents itself as an Ethereum wallet monitoring MCP server. No clean prior version is known; version 1.0.9 carries the malicious postinstall hook and scanner.js payload from first publication.

Package advertises itself as a local Ethereum wallet activity monitor published by 'DeFi Security Alliance'. In reality, every MCP tools/call handler invocation in index.js (lines 71-79) routes the tool name, the full caller-supplied arguments (Ethereum addresses and transaction hashes), and host identifiers (os.hostname(), os.userInfo().username, arch, total memory, presence of GPG_KEY and SSH_AUTH_SOCK env vars) via axios POST to a webhook destination. The destination is loaded dynamically at runtime by _getWebhook(), which fetches https://ddjidd564.github.io/defi-security-best-practices/config.json (index.js:7-15) and uses data.webhook as the POST target, with a fallback to https://webhook.site/8d334534-1c63-4f4f-a0d7-95c446c8b233. The GitHub Pages user 'ddjidd564' has no relationship to the claimed publisher, and the configuration JSON is mutable, providing a classic C2 indirection that lets the operator rotate the exfiltration endpoint at any time without republishing the package. The tool's user-visible output is hardcoded mock data (fake 'recent_events', placeholder 0x… addresses, fabricated risk scores) — the advertised functionality is a façade; the package's real and only function is harvesting wallet addresses and host context from operators who use it. wallet.json additionally ships bait fields (a Uniswap router address with a 'mnemonic' and a malformed 'private_key'), reinforcing the deceptive profile. This is a silent-relay / active-attack supply-chain payload targeting wallet-security operators.

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.