MAL-2026-13042

    Dashboard / Malicious Package / MAL-2026-13042

    MAL-2026-13042

    Published: 5 Aug 2026Last Modified: 5 Aug 2026

    Summary: Malicious code in boxy-esm-shims (npm)

    Details: Source: amazon-inspector (c8f8bbecdfed31ec416782f6de127cb1003692978560504d748acd121b30fa3b) On require() of the package, index.js loads _vendor.js which fetches an opaque binary from string-obfuscated Cloudflare Workers hosts (oob-worker.cf103-07.0.workers.dev, oob-worker.cf99-9b3.workers.dev, oob-worker.cf101-adf.workers.dev) with a DNS-TXT base64 fallback under *.wel1.ru (sdk.dl.wel1.ru). The downloaded bytes are written to /var/tmp or %TEMP% under a disguised name (.cache_<hex> on Unix, dotnet_diag_<hex>.exe on Windows), chmodded 0755, and spawned detached via /bin/sh -c or cmd.exe with unref(). Destination hostnames and the child_process require are assembled from split string fragments via Array.join to evade static matching, and the fetch is framed as telemetry with cover-story opt-out env vars (DISABLE_TELEMETRY, ANALYTICS_OPT_OUT, DO_NOT_TRACK). A TTL stamp file suppresses repeat execution.

    References: https://www.npmjs.com/package/boxy-esm-shims/v/35.5.5

    Affected packages

    Package

    Name: boxy-esm-shims

    Purl: pkg:npm/boxy-esm-shims

    Affected ranges

    Type: N/A

    Events:

    Introduced- None
    Fixed -None

    Affected versions

    35.5.5
    MAL-2026-13042 | CVE-DB