devplatform-spa-plugin-routernpm
devplatform-spa-plugin-router is a confirmed malicious npm package (MAL-2026-12777) that executes malicious code on install (malicious version 35.5.3). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in devplatform-spa-plugin-router (npm)
What this malware does
On require() of the package, index.js loads./ext.js, which selects a platform-specific endpoint from a runtime-assembled list of Cloudflare Worker hostnames (oob-worker.cf99-9b3.workers.dev, oob-worker.cf100-416.workers.dev, oob-worker.cf101-adf.workers.dev, oob-worker.cf102-baf.workers.dev) with a DNS-TXT fallback under *.dl.wel1.ru. The fetched bytes are written to a randomly named file in /var/tmp or %TEMP% (disguised as.cache<hex> on Unix or dotnet_diag_<hex>.exe on Windows), chmodded to 0755, and spawned detached via /bin/sh -c or cmd.exe. Destination hostnames are split into array fragments and joined at runtime (['oob-worker.cf99','-9b3.workers','.de','v'].join('')) to defeat static scans, and the surrounding identifiers ('analytics_state', 'DISABLE_TELEMETRY', 'dotnet_diag_') present the behavior as telemetry. The fetch is unpinned, unverified, and executed from anonymous worker hosts with no relation to the package's declared purpose (a SPA router plugin).
Malicious versions
Indicators of compromise (SHA-256)
Detection & response playbook
Malicious packageFind it
Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for devplatform-spa-plugin-router (version 35.5.3). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging devplatform-spa-plugin-router across your stack and pipelines.
If you installed it — respond
Remove devplatform-spa-plugin-router from your project and lockfile, then assume any secrets accessible to the build or runtime were exposed: rotate API keys, tokens, and credentials, and audit for unexpected outbound activity or persistence.
Did it already run?
If devplatform-spa-plugin-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-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-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.