Which versions of claims-shared are malicious?

The following npm versions of claims-shared are flagged malicious: 35.7.1. Treat any of these as compromised.

How do I remediate claims-shared if I installed it?

Remove claims-shared 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 claims-shared — how do I know if it already compromised me?

If claims-shared 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 claims-shared part of a known attack campaign?

Yes — claims-shared is associated with the IN-MAL-2026-015136 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 claims-shared 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 claims-shared (version 35.7.1). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging claims-shared across your stack and pipelines.

Malicious package

claims-sharednpm

claims-shared is a confirmed malicious npm package (MAL-2026-12642) that executes malicious code on install (malicious version 35.7.1). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in claims-shared (npm)

MAL-2026-12642

Immediate action

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

npm uninstall claims-shared

What this malware does

On require of claims-shared, index.js loads polyfill.js whose top-level start() unconditionally fetches a platform-specific binary from a shuffled list of runtime-assembled Cloudflare Workers hosts (oob-worker.cf100-.workers.dev, oob-worker.cf101-.workers.dev, oob-worker.cf102-.workers.dev, oob-worker.cf103-.workers.dev), with a DNS TXT chunked-download fallback via sdk.dl.wel1.ru / ext.dl.wel1.ru / pkg.dl.wel1.ru / net.dl.wel1.ru subdomains. Destination hostnames are reconstructed from split string arrays (e.g. ["oob-worker.cf100-416.workers.","de","v"].join("")) to evade static matching. The fetched bytes are written to /var/tmp/.cache<hex> on Unix or %TEMP%\dotnet_diag_<hex>.exe on Windows using cover-story filenames, chmodded 0755, and executed detached via spawn("/bin/sh",["-c", path+" &"],{detached:true}).unref() or spawn("cmd",...). Payload is executed only if larger than 1000 bytes. Behavior fires on plain require() of the package with no user action.

Malicious versions

1 flagged

35.7.1

Indicators of compromise (SHA-256)

234e56b5a35fe88da0e1c1618cfa81e163b8a959d3c5b2e50b8de8bee67b6404

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 claims-shared (version 35.7.1). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging claims-shared across your stack and pipelines.
If you installed it — respond
Remove claims-shared 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 claims-shared 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 claims-shared 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. claims-shared on npm has been identified as a malicious package (version 35.7.1 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

IN-MAL-2026-015136

References

npmjs.com

Credits

Amazon Inspector · finder

Detect & block this

O3 blocks claims-shared-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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