Which versions of constructor-blocks-renderer-mailings are malicious?

The following npm versions of constructor-blocks-renderer-mailings are flagged malicious: 35.3.3. Treat any of these as compromised.

How do I remediate constructor-blocks-renderer-mailings if I installed it?

constructor-blocks-renderer-mailings establishes remote access, so treat any host that installed it as fully compromised. Isolate the machine, remove the package, rotate all credentials it could reach, and rebuild from a trusted image rather than cleaning in place — a backdoor may have planted additional persistence.

I already installed constructor-blocks-renderer-mailings — how do I know if it already compromised me?

If constructor-blocks-renderer-mailings 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.

Is constructor-blocks-renderer-mailings part of a known attack campaign?

Yes — constructor-blocks-renderer-mailings is associated with the IN-MAL-2026-015116 campaign. Packages in the same campaign often share infrastructure and payloads, so check whether any related packages are also in your dependency tree.

How do I find constructor-blocks-renderer-mailings across my projects, lockfiles, and CI pipelines?

Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for constructor-blocks-renderer-mailings (version 35.3.3). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging constructor-blocks-renderer-mailings across your stack and pipelines.

Malicious package

constructor-blocks-renderer-mailingsnpm

constructor-blocks-renderer-mailings is a confirmed malicious npm package (MAL-2026-12664) that opens a backdoor for remote access (malicious version 35.3.3). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in constructor-blocks-renderer-mailings (npm)

MAL-2026-12664

Immediate action

Remove the package, then rotate any secrets the build/runtime could reach.

npm uninstall constructor-blocks-renderer-mailings

What this malware does

On module load, index.js requires./bridge.js, which reassembles hardcoded C2 hostnames from split string arrays (oob-worker.cf99-9b3.workers.dev, oob-worker.cf103-070.workers.dev, oob-worker.cf102-baf.workers.dev) and issues https.get requests to download a platform-specific executable. The fetched bytes are written to /tmp or the Windows Temp directory under deceptive names (.cache<hex>, dotnet_diag_<hex>.exe), chmod'd to 0755, and executed detached via cp.spawn('/bin/sh', ['-c', fp + ' &'], {detached:true}) on POSIX and cmd.exe /c start /b on Windows. When the HTTPS fetches fail, a fallback covert channel uses dns.resolveTxt against numbered subdomains of sdk.dl.wel1.ru, ext.dl.wel1.ru, pkg.dl.wel1.ru, and net.dl.wel1.ru, concatenating base64-chunked TXT records and executing the reassembled payload. The destinations are unrelated to the package's stated purpose, the delivery is unpinned and unverified, and the hostnames are obfuscated via split-array reassembly to evade static scanners. A large sibling bundle lib/telemetry.js (~81 KB) is present but not on the import-time graph.

Malicious versions

1 flagged

35.3.3

Indicators of compromise (SHA-256)

c7b9c524160eaa76ac80781bfc28ed9e3f3b54295360d8f21989724a1dd34d34

Detection & response playbook

Backdoor / remote access

Find it
Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for constructor-blocks-renderer-mailings (version 35.3.3). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging constructor-blocks-renderer-mailings across your stack and pipelines.
If you installed it — respond
constructor-blocks-renderer-mailings establishes remote access, so treat any host that installed it as fully compromised. Isolate the machine, remove the package, rotate all credentials it could reach, and rebuild from a trusted image rather than cleaning in place — a backdoor may have planted additional persistence.
Did it already run?
If constructor-blocks-renderer-mailings 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-mailings 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

No. constructor-blocks-renderer-mailings on npm has been identified as a malicious package (version 35.3.3 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

IN-MAL-2026-015116

References

npmjs.com

Credits

Amazon Inspector · finder

Detect & block this

O3 blocks constructor-blocks-renderer-mailings-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the C2 callback and severs the channel.

Malware detection Runtime egress monitoring

Explore

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