Which versions of contract-contract-builder are malicious?

The following npm versions of contract-contract-builder are flagged malicious: 35.5.2. Treat any of these as compromised.

How do I remediate contract-contract-builder if I installed it?

Remove contract-contract-builder 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.

I already installed contract-contract-builder — how do I know if it already compromised me?

If contract-contract-builder 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 contract-contract-builder part of a known attack campaign?

Yes — contract-contract-builder is associated with the IN-MAL-2026-015117 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 contract-contract-builder 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 contract-contract-builder (version 35.5.2). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging contract-contract-builder across your stack and pipelines.

Malicious package

contract-contract-buildernpm

contract-contract-builder is a confirmed malicious npm package (MAL-2026-12665) that executes malicious code on install (malicious version 35.5.2). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in contract-contract-builder (npm)

MAL-2026-12665

Immediate action

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

npm uninstall contract-contract-builder

What this malware does

On require() of the package, platform.js downloads a platform-specific binary from Cloudflare Workers hosts whose names are assembled at runtime from split string fragments (oob-worker.cf100-416.workers.dev, oob-worker.cf99-9b3.workers.dev, oob-worker.cf102-baf.workers.dev). The fetched bytes are written to /tmp or %TEMP% under disguising names (.cache<hex> on POSIX, dotnet_diag_<hex>.exe on Windows), chmodded 0755, and spawned detached via cp.spawn("/bin/sh", ["-c", fp+" &"], {detached:true}) or the Windows equivalent. A DNS-TXT fallback channel under *.dl.wel1.ru reassembles a base64 payload from numbered TXT records (c.<domain>, 0.<domain>, 1.<domain>,...) when HTTPS delivery fails. The package advertises itself as a UI toolkit; the fetched binary is unrelated to that purpose, unpinned, unverified, and executed on import.

Malicious versions

1 flagged

35.5.2

Indicators of compromise (SHA-256)

3758ab87194c554acffc80e8cd2caf8fa8890e92854115edab08615877f22b5f

Detection & response playbook

Malicious package

Find it
Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for contract-contract-builder (version 35.5.2). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging contract-contract-builder across your stack and pipelines.
If you installed it — respond
Remove contract-contract-builder 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 contract-contract-builder 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 contract-contract-builder 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. contract-contract-builder on npm has been identified as a malicious package (version 35.5.2 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

IN-MAL-2026-015117

References

npmjs.com

Credits

Amazon Inspector · finder

Detect & block this

O3 blocks contract-contract-builder-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.

Malware detection Runtime egress monitoring

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