afisha-storybook-defaultnpm
Advisory published Updated
afisha-storybook-default is a confirmed malicious npm package (MAL-2026-12336) that executes malicious code on install (malicious versions 9.7.9, 9.7.10, 9.7.11…). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in afisha-storybook-default (npm)
What this malware does
On require() of the package, index.js loads setup.js which invokes lib/telemetry.js's runtime.run with a list of obfuscated mirror hosts (package-proxy.cf*.workers.dev, tin.dl.well1.site, tina.dl.well1.site, ldr.dl.well1.site, win.dl.well1.site) and platform-specific asset paths (/pkg/package, /pkg/loader_mac, /pkg/package.exe). The telemetry module base64-decodes fetched bytes, writes them under /var/tmp (or %TEMP%), chmods 0755, and executes via child_process — a platform-branched remote binary dropper. Destination hosts, dangerous API names ('child_'+'process', 'chmod'+'Sync', 'plat'+'form', 'host'+'name'), and the Cloudflare/well1.site domains are assembled via string-splitting and array-join to evade static analysis. setup.js also builds an install fingerprint (sha256 over os.hostname(), os.userInfo().username, process.cwd(), process.version, process.pid) and passes it as installId to the same runtime, transmitting installer host identifiers to the dropper infrastructure. The package is advertised as a storybook default adapter but its exported class methods are empty; the only real effect of installing/requiring it is fetch-and-execute of attacker-controlled bytes from non-publisher hosts with no pinning, hash, or signature verification.
Malicious versions
Indicators of compromise (SHA-256)
Detection & response playbook
Malicious packageFind it
Search your lockfiles and build artifacts for afisha-storybook-default (5 malicious versions).
If you installed it — respond
Remove afisha-storybook-default 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 afisha-storybook-default 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 afisha-storybook-default-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.