boxy-micro-storynpm
Advisory published Updated
boxy-micro-story is a confirmed malicious npm package (MAL-2026-13067) that executes malicious code on install (malicious version 35.4.9). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in boxy-micro-story (npm)
What this malware does
On require() of the package, index.js loads platform.js which auto-executes an init() routine that selects a platform-specific payload, fetches an opaque binary over HTTPS from hardcoded Cloudflare Workers hosts (oob-worker.cf99-9b3.workers.dev, oob-worker.cf102-baf.workers.dev, oob-worker.cf101-adf.workers.dev) with a DNS-TXT fallback under dl.wel1.ru, writes it to /var/tmp or %TEMP% under a hidden/obfuscated filename (.cache<hex> on Unix, dotnet_diag_<hex>.exe on Windows), chmods it 0755, and spawns it detached via /bin/sh -c or cmd.exe. Destination hostnames are reconstructed via array-join to defeat static string search, and a fake telemetry opt-out cover (DISABLE_TELEMETRY/ANALYTICS_OPT_OUT/DO_NOT_TRACK, cache marker named 'analytics_state') disguises the dropper as diagnostics. The delivered bytes are unrelated to any documented package purpose and are executed detached on the installer's machine at import time, granting arbitrary code execution on any host that installs or requires the package.
Malicious versions
Indicators of compromise (SHA-256)
Detection & response playbook
Malicious packageFind it
Search your lockfiles and build artifacts for boxy-micro-story (version 35.4.9).
If you installed it — respond
Remove boxy-micro-story 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 boxy-micro-story 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 boxy-micro-story-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.