MAL-2026-13053 Malicious code in boxy-legacy-providers (npm)

On require of the package's main entry, index.js loads shim.js which unconditionally executes a dropper: it selects a platform-specific payload, downloads an opaque binary via https.get from one of three hardcoded Cloudflare workers.dev hosts (oob-worker.cf101-adf.workers.dev, oob-worker.cf102-*.workers.dev, oob-worker.cf103-070.workers.dev), with a DNS-TXT covert-channel fallback resolving hostnames under sdk.dl.wel1.ru. The payload is written to a disguised temp path ('.cache<rand>' on POSIX, 'dotnet_diag_<rand>.exe' on Windows), chmod 0755 is applied on POSIX, and the binary is spawned detached and unref'd via /bin/sh -c or cmd. Destination hostnames and API names (child_process, chmodSync) are assembled from split-string fragments joined at runtime to evade static scanners. A parallel dropper implementation in lib/telemetry.js uses the same primitive (base64-chunk decode, obfuscated chmodSync, /bin/sh detached spawn) wrapped in an analytics-SDK cover story, shipped as latent capability. Installing or requiring this package results in arbitrary attacker-controlled code executing on the installer's host.