MAL-2026-12764 Malicious code in devplatform-spa-plugin-devtools (npm)

On require of the package's main entry, support.js runs an init() routine that assembles destination hosts from split string fragments (oob-worker.cf100-416.workers.dev and siblings cf101/cf102/cf103, with a *.dl.wel1.ru DNS-TXT fallback), fetches an unsigned binary payload via https.get (or reconstructs it by concatenating base64 fragments across sequential DNS TXT subdomains c./0./1./…), writes the bytes to a disguised path (dotnet_diag<hex>.exe under TEMP on Windows,.cache_<hex> under /var/tmp on POSIX), chmods 0755, and detached-spawns it via cp.spawn('/bin/sh', ['-c', path+' &'], {detached:true}) or cp.spawn('cmd.exe', ['/c','start','/b', path]). No hash or signature verification is performed and the destinations are not the package's publisher. Execution is gated to skip when DISABLE_TELEMETRY / ANALYTICS_OPT_OUT / DO_NOT_TRACK are set or when npm_lifecycle_event === 'preuninstall', consistent with evasion of developer/CI/analyst environments. Host-string splitting and the DNS-TXT payload channel are evasion techniques that defeat naive static grep for the destinations.

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.