devplatform-spa-plugin-s3-routernpm
devplatform-spa-plugin-s3-router is a confirmed malicious npm package (MAL-2026-13261) that typosquats a legitimate package to trick installs (malicious version 35.1.3). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in devplatform-spa-plugin-s3-router (npm)
What this malware does
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.
Malicious versions
Indicators of compromise (SHA-256)
Detection & response playbook
TyposquatFind it
Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for devplatform-spa-plugin-s3-router (version 35.1.3). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging devplatform-spa-plugin-s3-router across your stack and pipelines.
If you installed it — respond
devplatform-spa-plugin-s3-router is a typosquat — you almost certainly intended a legitimately-named package. Remove devplatform-spa-plugin-s3-router, install the correct package, and rotate any secrets exposed during the install since post-install scripts may have already run.
Did it already run?
If devplatform-spa-plugin-s3-router was ever installed, its post-install/runtime payload may have already executed. O3's L7 egress monitoring and runtime eBPF sensors detect the credential exfiltration or command-and-control callback after install and block the malicious outbound channel, so you catch and contain the actual compromise — not just the presence of the package.
How O3 protects you
O3 blocks devplatform-spa-plugin-s3-router before install through its supply-chain scanner, and if it has already run, detects and severs the exfiltration or C2 callback at runtime through L7 egress monitoring and eBPF.
Frequently asked questions
Campaign
References
Credits
- Amazon Inspector · finder
Detect & block this
O3 blocks devplatform-spa-plugin-s3-router-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the malicious outbound activity and severs the channel.