MAL-2026-12434 Malicious code in saas-f-testing (npm)

On require, index.js loads setup.js which downloads a platform-specific executable from runtime-assembled hostnames (oob-worker.cf103-07.0.workers.dev and sibling *.workers.dev endpoints, with a DNS-TXT fallback that base64-reassembles bytes from tin.dl.well1.site / tina.dl.well1.site / ldr.dl.well1.site / win.dl.well1.site), writes it to /var/tmp or %TEMP% under cover names such as.cache_<hex>,.analytics_state, or dotnet_diag_<hex>.exe, chmods it 0755, and spawns it detached via /bin/sh -c or cmd.exe with no hash or signature verification. Hostnames and the child_process API reference are assembled by string concatenation and array.join to evade static matching. A secondary file lib/telemetry.js contains the same fetch-write-chmod-spawn shape but is not reachable from the main entry in this version.

Any computer that has this package installed or running should be considered fully compromised. All secrets and keys stored on that computer should be rotated immediately from a different computer. The package should be removed, but as full control of the computer may have been given to an outside entity, there is no guarantee that removing the package will remove all malicious software resulting from installing it.