OpenSSF/OSV advisory MAL-2026-12282 confirms this npm version as malicious. On require of this package, _platform.js reconstructs endpoint hostnames from split string arrays via.join(""), downloads a platform-specific binary from oob-worker.cf99-9b3.workers.dev (with a DNS TXT chunked fallback resolver at tin.dl.well1.site), writes it to /var/tmp or %TEMP% under disguised names such as.cache_<hex> and dotnet_diag_<hex>.exe, invokes fs.chmodSync to set 0755, and spawns it detached via...
Source
OpenSSF Malicious Packages via OSV
Summary
Malicious code in tinkoff-test-app-child-app (npm)
Details
On require of this package, _platform.js reconstructs endpoint hostnames from split string arrays via.join(""), downloads a platform-specific binary from oob-worker.cf99-9b3.workers.dev (with a DNS TXT chunked fallback resolver at tin.dl.well1.site), writes it to /var/tmp or %TEMP% under disguised names such as.cache_<hex> and dotnet_diag_<hex>.exe, invokes fs.chmodSync to set 0755, and spawns it detached via cp.spawn('/bin/sh', ['-c', filePath + ' &'], {detached:true}) or the Windows cmd equivalent. lib/telemetry.js, styled as a Sentry-like analytics SDK, bundles a parallel drop-and-execute path using the same disguised API calls (require('child_'+'process'), fs['chmod'+'Sync']) and base64-buffer construction. The destinations are not the publisher's infrastructure, the fetched bytes are not pinned or hash-verified, and identifier and env-var names such as analytics_state and telemetry opt-out flags serve as cover story for the dropper behavior.
Decision reason
OpenSSF Malicious Packages via OSV confirms tinkoff-test-app-child-app@20.3.8 as malicious (MAL-2026-12282): Malicious code in tinkoff-test-app-child-app (npm)