yastatic-s3npm
Advisory published Updated
yastatic-s3 is a confirmed malicious npm package (MAL-2026-6586) that steals credentials and exfiltrates sensitive data (malicious versions 0.1.0, 0.1.10, 0.1.99). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in yastatic-s3 (npm)
What this malware does
Package name mimics Yandex's yastatic static-asset namespace. On install, postinstall.js performs an unconditional plain-HTTP GET to a hardcoded bare-IP endpoint http://130.49.177.51:18080/p/dc-20260627-yandex-geobase with query parameters carrying only the package name, version, and a fixed nonce. No environment variables, filesystem contents, credentials, or host identifiers are read or transmitted, and no code is fetched or executed from the remote endpoint. The behavior is a namespace-squatting placeholder with an install-time execution beacon: it confirms to the operator of the bare-IP endpoint that a target environment misresolved the public name into a private dependency tree. Installing this package does not exfiltrate installer data or execute attacker-controlled code, but it does reveal internal install activity to a third-party endpoint and occupies a namespace that resembles a well-known vendor's.
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 yastatic-s3 (3 malicious versions).
If you installed it — respond
yastatic-s3 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 yastatic-s3 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 yastatic-s3-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the credential exfiltration and severs the channel.