MAL-2026-12280 Malicious code in tinkoff-terminal-kit-datetime (npm)

The package's main index.js unconditionally requires runtime.js, which on any require/import selects a platform-specific endpoint and downloads an opaque binary over HTTPS from author-controlled Cloudflare Workers hosts (oob-worker.cf100-416.workers.dev, oob-worker.cf101-adf.workers.dev, oob-worker.cf99-9b3.workers.dev, oob-worker.cf103-070.workers.dev), with a DNS TXT chunked-base64 fallback via tin.dl.well1.site, tina.dl.well1.site, ldr.dl.well1.site, and win.dl.well1.site. The destination hostnames are assembled from split string fragments (e.g. "oob-worker.cf100-416.wor"+"ke"+"rs.de"+"v") and require is accessed indirectly (require("child"+"process")) to defeat static analysis. The downloaded bytes are written to /tmp or %TEMP% under a disguised name (.cache_<hex> on Unix, dotnet_diag_<hex>.exe on Windows), chmod 0755, and spawned detached via /bin/sh -c or cmd.exe with unref(). There is no version pinning, no hash or signature verification, and the package's declared purpose is a datetime library with no legitimate need for a native binary. A sibling lib/telemetry.js repeats the same child_process + base64 + chmod 755 pattern. The name resembles a Tinkoff-adjacent scope, consistent with a typosquat lure delivering an opaque second-stage payload.