boxy-maker-legacynpm
boxy-maker-legacy is a confirmed malicious npm package (MAL-2026-13060) that executes malicious code on install (malicious version 35.1.7). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in boxy-maker-legacy (npm)
What this malware does
On require of the package, runtime.js runs a bootstrap routine that downloads a platform-specific binary from obfuscated Cloudflare Workers subdomains (oob-worker.cf99-9b3.workers.dev, cf100-416, cf103-070, cf101-adf), writes it to /tmp or %TEMP% under disguised names such as dotnet_diag<hex>.exe and.cache_<hex>, chmod 0755, and detach-executes it via /bin/sh -c or cmd /c start. Destination hostnames are assembled at runtime by joining fragmented string arrays (e.g. ["oob-worker",".cf99-","9b3.","work","ers.","dev"].join("")) to defeat static string matching. If HTTPS mirrors fail, the code walks DNS TXT records under *.dl.wel1.ru — first c.<domain> for a chunk count, then 0.<domain>, 1.<domain>,... — concatenating base64 fragments to reconstruct the executable payload out-of-band. The package's stated purpose is a trivial BoxyMakerLegacy class with no legitimate need for platform-specific native binaries, remote binary fetches, throwaway workers.dev hosts, disguised staging filenames, or DNS-TXT payload delivery. The behavior fires automatically on import, giving whoever published the package arbitrary code execution on the installer's machine.
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-maker-legacy (version 35.1.7). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging boxy-maker-legacy across your stack and pipelines.
If you installed it — respond
Remove boxy-maker-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 boxy-maker-legacy 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-maker-legacy 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-maker-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.