@whatnot-web/www-legacynpm
Advisory published Updated
@whatnot-web/www-legacy is a confirmed malicious npm package (MAL-2026-5622) that executes malicious code on install (malicious versions 99.1.1, 99.1.2). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in @whatnot-web/www-legacy (npm)
What this malware does
@whatnot-web/[email protected] is a dependency-confusion shell targeting the Whatnot org scope. The package ships an empty library (index.js exports {}), a generic description, blank author, and an inflated version (99.1.1) — the canonical dependency-confusion shape designed to win resolution against an internal package of the same name. On npm install, postinstall.js collects os.hostname(), os.userInfo().username, process.cwd(), and a 2-level directory listing of the working directory, base64-encodes the JSON payload, and POSTs it via HTTPS to the hardcoded interactsh collector wybqtvzmfhssbvhokfgb61yfn41sqvc9c.oast.fun. A hex-encoded DNS-lookup fallback to the same host is included to defeat HTTPS egress filtering. The collected information identifies internal build hosts and source-tree layouts and is suitable for staging follow-on attacks against the targeted organization.
The OpenSSF Package Analysis project identified '@whatnot-web/www-legacy' @ 99.1.2 (npm) as malicious.
It is considered malicious because:
- The package communicates with a domain associated with malicious activity.
Malicious versions
Indicators of compromise (SHA-256)
Detection & response playbook
Malicious packageFind it
Search your lockfiles and build artifacts for @whatnot-web/www-legacy (2 malicious versions).
If you installed it — respond
Remove @whatnot-web/www-legacy from your project and lockfile, then assume any secrets accessible to the build or runtime were exposed: rotate API keys, tokens, and credentials, and audit for unexpected outbound activity or persistence.
Did it already run?
If @whatnot-web/www-legacy 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
- OpenSSF: Package Analysis · finder
Detect & block this
O3 blocks @whatnot-web/www-legacy-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the malicious outbound activity and severs the channel.