Malicious code in devplatform-spa-plugin-s3-router (npm)
On require() of devplatform-spa-plugin-s3-router, index.js loads _helpers.js which runs a bootstrap routine at module load. The code assembles Cloudflare Workers hostnames (oob-worker.cf10-0-416.workers.dev, oob-worker.cf99-9b3.workers.dev, oob-worker.cf101-adf.workers.dev) via string-splitting and.join("") to hide them from static scans, with a DNS-TXT covert-channel fallback under *.dl.wel1.ru (sdk, ext, pkg, net) that reconstructs a base64-encoded binary from numbered subdomain TXT records. The retrieved binary is written to /tmp or the Windows temp directory under a disguised name mimicking Microsoft dotnet diagnostics (dotnet_diag_<hex>.exe or.cache_<hex>), chmod 0755'd, and spawned detached via /bin/sh -c or cmd /c start. A.analytics_state file rate-limits re-execution. A sibling lib/telemetry.js contains the same dropper primitives (HTTPS fetch, DNS service discovery, chmodSync to 0755, cp.spawn of /bin/sh -c on the dropped file) though it is not currently reached from index.js. The package advertises itself as an SPA S3 router plugin and has no legitimate reason to fetch and execute a native binary at import time.
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.
MAL-2026-13261 is recorded against 1 package.
Published on 5 August 2026 and last revised on 6 August 2026. No public exploit is currently recorded for this entry. Record sourced from OSV.
Details
Affected Packages
| Software | From version | Fixed in |
|---|---|---|
| devplatform-spa-plugin-s3-router | — | — |
References
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