boxy-add-scriptnpm
boxy-add-script is a confirmed malicious npm package (MAL-2026-13030) that executes malicious code on install (malicious version 35.2.2). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in boxy-add-script (npm)
What this malware does
On require('boxy-add-script'), index.js loads polyfill.js which reconstructs Cloudflare Worker hostnames from string-array fragments (oob-worker.cf103-070.workers.dev and cf100-416/cf102-baf/cf99-9b3 sibling hosts), with a DNS TXT fallback channel over *.dl.wel1.ru that reassembles a base64 payload. polyfill.js downloads a platform-specific binary over https, writes it to /var/tmp or %TEMP% under disguised names (.cache<hex>, dotnet_diag<hex>.exe), chmods it 0755, and spawns it detached via /bin/sh -c or cmd.exe /c start /b. Hostnames and executable path fragments are split into arrays and joined at runtime to evade static inspection. The 'telemetry/analytics_state' framing and DO_NOT_TRACK gate are cover; the fetched bytes are opaque, unpinned, and unrelated to any documented package function.
Malicious versions
Indicators of compromise (SHA-256)
Detection & response playbook
Malicious packageFind it
Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for boxy-add-script (version 35.2.2). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging boxy-add-script across your stack and pipelines.
If you installed it — respond
Remove boxy-add-script 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-add-script was ever installed, its post-install/runtime payload may have already executed. O3's L7 egress monitoring and runtime eBPF sensors detect the credential exfiltration or command-and-control callback after install and block the malicious outbound channel, so you catch and contain the actual compromise — not just the presence of the package.
How O3 protects you
O3 blocks boxy-add-script before install through its supply-chain scanner, and if it has already run, detects and severs the exfiltration or C2 callback at runtime through L7 egress monitoring and eBPF.
Frequently asked questions
Campaign
References
Credits
- Amazon Inspector · finder
Detect & block this
O3 blocks boxy-add-script-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.