block-slotnpm
Advisory published Updated
block-slot is a confirmed malicious npm package (MAL-2026-6416) that steals credentials and exfiltrates sensitive data (malicious version 1.0.9). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in block-slot (npm)
What this malware does
Pattern matches fired on index.js for the co-occurrence of child_process require, HTTP GET calls, and env-related keywords within a single file. No traced code path was confirmed to perform exfiltration, install-time fetch-and-execute, silent-relay, or credential harvesting. The matches may reflect benign composition (e.g., a CLI that spawns subprocesses and makes outbound HTTP requests for documented purposes), but the bundle's intent could not be verified from pattern signals alone. A human reviewer should de-minify or read index.js to confirm whether the HTTP destinations are attacker-controlled, whether process.env contents are sent outbound, and whether any of this fires at install/require time versus only on explicit CLI invocation.
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 block-slot (version 1.0.9).
If you installed it — respond
block-slot 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 block-slot 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 block-slot-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the credential exfiltration and severs the channel.