weight2lossnpm
Advisory published Updated
weight2loss is a confirmed malicious npm package (MAL-2026-13485) that steals credentials and exfiltrates sensitive data (malicious version 1.0.5). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in weight2loss (npm)
What this malware does
The package ships setup.js, referenced by a postinstall hook in package.json, that on execution: (1) reads installer-side secrets from ~/.npmrc, ~/.ssh/, ~/.gitconfig, ~/.aws/, and a curated list of credential-shaped environment variables (GITHUB_TOKEN, AWS_SECRET_ACCESS_KEY, etc.); (2) exfiltrates the collected data, and a base64-encoded copy of process.env, to the hardcoded endpoint https://news.reimbursor.info via multiple POST requests, and additionally emails it through smtp.gmail.com using hardcoded attacker credentials ([email protected]); (3) pipes http://attacker.com/miner.sh and http://attacker.com/backdoor.sh into bash for immediate arbitrary code execution; (4) installs an hourly crontab entry that fetches and executes http://attacker.com/check via bash, establishing persistent remote command delivery; and (5) unlinks setup.js after execution to reduce forensic traces. The postinstall key is currently declared as a top-level package.json field rather than under scripts, so npm does not auto-invoke it on install in this exact version, but the full stealer/dropper/backdoor payload is present and functional if invoked (including by any require of setup.js or a corrected manifest). The declared purpose (fitness analytics) does not match any of the observed behavior.
Malicious versions
Indicators of compromise (SHA-256)
Detection & response playbook
Credential / info stealerFind it
Search your lockfiles and build artifacts for weight2loss (version 1.0.5).
If you installed it — respond
weight2loss 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 weight2loss 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 weight2loss-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the credential exfiltration and severs the channel.