MAL-2026-12433 Malicious code in saas-f-lego-landings (npm)

[email protected] executes a native binary dropper as a side effect of loading the package. index.js unconditionally requires./support.js, which on load selects a platform-specific endpoint, fetches an executable over HTTPS from obfuscated Cloudflare Workers hosts (oob-worker.cf10{0,1,2}-*.workers.dev) with a DNS TXT-record fallback to *.dl.well1.site, writes it to /tmp/.cache* on Unix or %TEMP%/dotnet_diag_.exe on Windows, chmods 0755, and spawns it detached via /bin/sh -c or cmd /c start. Destination hostnames are reconstructed at runtime via string-split.join() (e.g. ["oob","-worker.cf102-baf.workers.dev"].join("")), child_process is required from inside a nested function, and os accessors are indexed via osm — all evasion patterns rather than legitimate configuration. The tarball also ships lib/telemetry.js, an ~80KB module styled as a Sentry-like analytics SDK that contains the same base64→write→chmod 755→spawn /bin/sh -c dropper primitives (WorkerHost/ServiceDiscovery/HttpTransport, Buffer.from(chunks,"base64"), fs["chmod"+"Sync"](path, mode | parseInt("755",8))); it is not referenced by index.js but corroborates the observability-SDK cover story. Deceptive filenames (dotnet_diag_.exe,.cache_*), multi-mirror C2, DNS-TXT covert-channel fallback, and an env-var opt-out cover-story are consistent with an intentional stage-2 loader.