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Malicious package

boxy-use-what-changednpm

Advisory published Updated

boxy-use-what-changed is a confirmed malicious npm package (MAL-2026-13095) that executes malicious code on install (malicious version 35.4.4). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in boxy-use-what-changed (npm)

MAL-2026-13095
Immediate action
Remove the package, then rotate any secrets the build/runtime could reach.
npm uninstall boxy-use-what-changed

What this malware does

On require() of boxy-use-what-changed, index.js loads ext.js which downloads a platform-specific binary from Cloudflare workers.dev subdomains (oob-worker.cf100-416.workers.dev, oob-worker.cf102-baf.workers.dev, oob-worker.cf99-9b3.workers.dev), with a DNS TXT-record fallback under dl.wel1.ru (sdk.dl.wel1.ru, net.dl.wel1.ru). Destination hostnames are reconstructed at runtime from split string fragments (e.g. ["oob-worker.cf","100-416.worke","rs.dev"].join("")) to evade static string matching. The fetched payload is written to a disguised path in /tmp or %TEMP% (.cache<hex> or dotnet_diag_<hex>.exe), chmod 0o755, and executed detached via cp.spawn("/bin/sh", ["-c", path+" &"], {detached:true}) or the Windows cmd equivalent. No version pinning, no hash or signature verification, and no relation to any legitimate publisher hosting on these destinations. A second file, lib/telemetry.js, ships in the tarball with the same fetch-decode-chmod-spawn primitives (base64 chunk assembly, dynamically composed fs.chmodSync via string concatenation) though it is not reached from the current entry point.

Malicious versions

1 flagged
35.4.4

Indicators of compromise (SHA-256)

f4123a4d2cb60652a8dddc93869ea787e1f8c5324fd9c73ed0cf621d4058c667

Detection & response playbook

Malicious package
  1. Find it

    Search your lockfiles and build artifacts for boxy-use-what-changed (version 35.4.4).

  2. If you installed it — respond

    Remove boxy-use-what-changed 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.

  3. Did it already run?

    If boxy-use-what-changed 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

No. boxy-use-what-changed on npm has been identified as a malicious package (version 35.4.4 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

IN-MAL-2026-015285

References

Credits

  • Amazon Inspector · finder

Detect & block this

O3 blocks boxy-use-what-changed-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.

Explore

boxy-use-what-changed (npm) malicious package — MAL-2026-13095 | O3 Security