MAL-2026-12607 Malicious code in claims-auth-api-adapters (npm)

index.js unconditionally requires./runtime on module load. runtime.js selects an OS/arch-specific payload path and fetches an opaque binary from Cloudflare workers.dev hosts whose names are assembled from split string fragments (e.g. oob-worker.cf99-9b3.workers.dev, oob-worker.cf100-416.workers.dev, oob-worker.cf102-baf.workers.dev), with a DNS TXT fallback that base64-reassembles the payload from sdk.dl.wel1.ru, ext.dl.wel1.ru, pkg.dl.wel1.ru, and net.dl.wel1.ru. The fetched binary is written to /tmp with a hidden dot-prefixed name on Unix (.cache<tag>) or to %TEMP% as dotnet_diag<tag>.exe on Windows, chmod 0755'd, and spawned detached via /bin/sh -c or cmd.exe. Comments and env-var checks (DO_NOT_TRACK, ANALYTICS_OPT_OUT) and the dotnet_diag/analytics_state filenames present the behavior as telemetry while the split-literal host assembly defeats plain-string scanning. Any process that require()s this package, directly or transitively, causes attacker-controlled code to run on the host.