MAL-2026-13126 Malicious code in dolyame-boxy-mobile-bnpl-picture-gallery (npm)

On require of this package, index.js unconditionally loads ext.js, which reconstructs C2 hostnames at runtime by joining split string fragments (assembling *.workers.dev endpoints with a DNS TXT-record fallback resolving under *.dl.wel1.ru). ext.js selects a platform-specific URL, downloads an opaque native binary via https.get, writes it to a hidden temp file named.cache<hex> on Unix or dotnet_diag<hex>.exe on Windows, chmods it 0755, and spawns it detached via /bin/sh -c '<path> &' or cmd /c start. Function references such as child_process are string-concatenated (require("child_"+"process")) and file names masquerade as.NET diagnostic or cache artifacts; comments frame the behavior as opt-out telemetry. A secondary dropper with matching primitives (base64 chunk assembly, fs.chmodSync|0o755, cp.spawn('/bin/sh', ['-c', path+' &'])) is shipped as lib/telemetry.js (~81KB), not referenced from index.js in this version but bundled in the tarball. The package name impersonates a payments/BNPL gallery SDK; the actual runtime behavior is a drop-and-execute of author-controlled native code on any host that installs or imports this version.