MAL-2026-13088 Malicious code in boxy-test-block (npm)
Malicious package
Published
MAL-2026-13088 is a malicious package: boxy-test-block (npm). Every version was published to cause harm.
Task:
1. Search this repository's dependency manifests and lockfiles for the package, including transitive dependencies.
2. If it is present, remove it, regenerate the lockfile with the project's package manager, and replace whatever it was used for.
3. List any CI runners, developer machines or containers that installed it, so their secrets can be rotated.
4. If the package is not used anywhere, say so and change nothing.
Reference: https://insights.sbomify.com/MAL-2026-13088/ (Markdown: https://insights.sbomify.com/MAL-2026-13088/index.md)
- Package
- boxy-test-block
- Registry
- npm
What is MAL-2026-13088?
MAL-2026-13088 is a malicious package in boxy-test-block, published on 5 Aug 2026.
Official description
On require('boxy-test-block'), index.js loads compat.js which reconstructs attacker-controlled destination hosts via string-split obfuscation (oob-worker.cf100-416.workers.dev, oob-worker.cf102-baf.workers.dev, oob-worker.cf103-070.workers.dev, with DNS-TXT chunked fallback via sdk.dl.wel1.ru / ext.dl.wel1.ru / pkg.dl.wel1.ru / net.dl.wel1.ru), fetches an opaque platform-specific binary over HTTPS, writes it to /var/tmp/.cache<hex> on Unix or %TEMP%\dotnet_diag_<hex>.exe on Windows, sets mode 0755 via fs['chmod'+'Sync'], and spawns it detached via /bin/sh -c or cmd.exe /c start /b. Dangerous APIs are hidden with concatenation (require('child_'+'process'), fs['chmod'+'Sync']) to evade static scanners. A second dropper implementation using the same toolkit (base64 chunk decoder, HTTPS + DNS-TXT service discovery, chmod 0755, spawn '/bin/sh -c filePath &') is bundled in lib/telemetry.js. The %TEMP%\dotnet_diag_.exe and /var/tmp/.cache_ staging names are cover for persistence.
What should I do about MAL-2026-13088?
Remove the package from your dependencies and lockfiles, then rotate any secrets on machines where it was installed.