web-mainnpm
Advisory published Updated
web-main is a confirmed malicious npm package (MAL-2026-16153) that steals credentials and exfiltrates sensitive data (malicious version 22.1.2). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in web-main (npm)
What this malware does
package.json declares preinstall: node index.js, causing index.js to execute automatically on npm install. The script collects os.hostname(), os.userInfo() (username/uid/gid/shell), platform, arch, homedir, and the stdout of whoami, id, and pwd via child_process.exec, then POSTs the aggregated JSON to a hardcoded endpoint at https://smi54v4uvb9q7ve5t6fnyro16scj0co1.oastify.com/system-info (a Burp Collaborator out-of-band host). No legitimate functionality is present; the package's sole effect on install is host reconnaissance and exfiltration to an attacker-controlled OOB collector.
Malicious versions
Indicators of compromise (SHA-256)
Detection & response playbook
Credential / info stealerFind it
Search your lockfiles and build artifacts for web-main (version 22.1.2).
If you installed it — respond
web-main 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 web-main 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 web-main-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the credential exfiltration and severs the channel.