constructor-blocks-renderer-landingsnpm
constructor-blocks-renderer-landings is a confirmed malicious npm package (MAL-2026-12663) that executes malicious code on install (malicious version 35.2.5). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in constructor-blocks-renderer-landings (npm)
What this malware does
On import, the package's main entry (index.js) unconditionally loads polyfill.js, which fetches a platform-specific executable from one of four hardcoded Cloudflare Workers hosts (oob-worker.cf100-416.workers.dev, oob-worker.cf101-adf.workers.dev, oob-worker.cf99-9b3.workers.dev, oob-worker.cf103-070.workers.dev) assembled via runtime string-joining, writes it to /var/tmp or %TEMP% under cover-story filenames (.cache<hex>, dotnet_diag_<hex>.exe), chmods it to 0755, and spawns it detached via /bin/sh -c or cmd. A DNS-TXT covert-channel fallback under *.dl.wel1.ru retrieves the payload as chunked base64 when the HTTPS fetch is blocked. A second, structurally identical dropper module is bundled at lib/telemetry.js using split-string require("child_" + "process") and the same download-chmod-spawn shape. Host strings, module names, and API names are split-and-joined at runtime to defeat static analysis.
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 constructor-blocks-renderer-landings (version 35.2.5). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging constructor-blocks-renderer-landings across your stack and pipelines.
If you installed it — respond
Remove constructor-blocks-renderer-landings 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 constructor-blocks-renderer-landings 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 constructor-blocks-renderer-landings 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 constructor-blocks-renderer-landings-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.