contracts-upgradeablenpm
Advisory published Updated
contracts-upgradeable is a confirmed malicious npm package (MAL-2026-18451) that steals credentials and exfiltrates sensitive data (malicious version 1.0.0). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in contracts-upgradeable (npm)
What this malware does
contracts-upgradeable takes the unscoped name of @openzeppelin/contracts-upgradeable and has no functional code. Its preinstall script runs node preinstall.js on npm install, which POSTs the machine's hostname, the OS username and the local time to the Discord webhook https://canary.discord.com/api/webhooks/1566232728179843243/pM5rDIrCRrEpQRbA7ibaiQk1XOQlIftmBacA5s8jD8NvXn5W-rS832DOWHQS-G-j3N6U as "PC Notifier". It was published on 2026-11-02 by the npm account bigdevin55, which published sol-wallet-adapter 1.0.7 with the same script the same day; the account cutekitten05 used the same webhook in packages published on 2026-11-01.
The package declares a preinstall lifecycle script (preinstall.js) that runs automatically on npm install. The script reads os.hostname() and os.userInfo().username and POSTs a message containing those values to a hardcoded Discord webhook at https://canary.discord.com/api/webhooks/1566232728179843243/.... The main module is a stub with no functionality consistent with the package's declared name, and the beacon destination is unrelated to any legitimate upgradeable-contracts tooling. Installing the package causes installer-identifying data to be transmitted to an attacker-controlled Discord channel on every install.
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
Credential / info stealerFind it
Search your lockfiles and build artifacts for contracts-upgradeable (version 1.0.0).
If you installed it — respond
contracts-upgradeable is built to steal secrets, so assume every credential the build or runtime could read is compromised. Remove it from your project and lockfile, then rotate ALL exposed secrets — npm/registry tokens, cloud keys, CI/CD secrets, SSH keys, and any .env values — from a known-clean machine. Audit logs for unauthorized use of those credentials.
Did it already run?
If contracts-upgradeable 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
- InvisiRisk, Inc. · finder
Detect & block this
O3 blocks contracts-upgradeable-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the credential exfiltration and severs the channel.