mev-shieldnpm
Advisory published Updated
mev-shield is a confirmed malicious npm package (MAL-2026-4609) that executes malicious code on install (malicious version 1.4.2). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in mev-shield (npm)
What this malware does
The package advertises itself as an 'MEV protection layer for Ethereum trading bots' but does the opposite. On npm install, a postinstall script base64-decodes the URL http://165.22.200.211:8545 (an attacker-controlled Ethereum JSON-RPC endpoint, labeled 'honeypot RPC' in the package's own comments) and writes it into the installer's .env across multiple RPC variables (ETHEREUM_RPC, ETH_RPC, WEB3_RPC, RPC_ENDPOINT). On require(), config-manager.js further mutates the consumer's project files in place: it prepends RPC_URL=http://165.22.200.211:8545 to scripts in package.json, injects the same env entry into docker-compose.yml, and rewrites rpc_url fields in any config.json / bot-config.json / settings.json / config/trading.json it finds in the working directory. An optimizeRPC() 'benchmark' is rigged so the attacker IP always wins regardless of measured latency (// THE MAGIC: Our honeypot always "wins"). Persistence is layered on top: a preuninstall keepalive script intentionally leaves the honeypot RPC in .env after the package is removed, and a git-hooks.js module installs a .git/hooks/pre-commit hook that re-executes node -e "require('mev-shield');" on every commit to re-inject the malicious RPC if it has been cleaned up. The postinstall payload is deliberately obfuscated with base64 and _0x-prefixed identifiers, with a self-incriminating comment 'Obfuscated module loader - makes static analysis harder'. Net effect on installers: every pending Ethereum transaction submitted by the consumer's trading bot is routed through the attacker, enabling frontrunning and sandwich attacks against the installer's funds, and the redirection survives uninstall.
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.
Malicious versions
Indicators of compromise (SHA-256)
Detection & response playbook
Malicious packageFind it
Search your lockfiles and build artifacts for mev-shield (version 1.4.2).
If you installed it — respond
Remove mev-shield from your project and lockfile, then assume any secrets accessible to the build or runtime were exposed: rotate API keys, tokens, and credentials, and audit for unexpected outbound activity or persistence.
Did it already run?
If mev-shield was installed, its post-install payload may already have run. Removing the package does not undo that — check outbound connections and credential use from the install window onward.
Frequently asked questions
Campaign
References
Credits
- Amazon Inspector · finder
Detect & block this
O3 blocks mev-shield-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the malicious outbound activity and severs the channel.