Which versions of claims-block-visibility are malicious?

The following npm versions of claims-block-visibility are flagged malicious: 35.3.8. Treat any of these as compromised.

How do I remediate claims-block-visibility if I installed it?

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

If claims-block-visibility 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-block-visibility part of a known attack campaign?

Yes — claims-block-visibility is associated with the IN-MAL-2026-015169 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-block-visibility 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-block-visibility (version 35.3.8). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging claims-block-visibility across your stack and pipelines.

Malicious package

claims-block-visibilitynpm

claims-block-visibility is a confirmed malicious npm package (MAL-2026-12609) that executes malicious code on install (malicious version 35.3.8). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in claims-block-visibility (npm)

MAL-2026-12609

Immediate action

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

npm uninstall claims-block-visibility

What this malware does

On require('claims-block-visibility'), index.js loads polyfill.js which unconditionally runs a setup routine that selects an OS-specific endpoint, downloads a binary from one of several string-concatenation-obfuscated hosts under *.workers.dev, and falls back to a chunked base64-over-DNS-TXT channel under sdk.dl.wel1.ru / ext.dl.wel1.ru / pkg.dl.wel1.ru / net.dl.wel1.ru when HTTPS is unavailable. The fetched bytes are written to a temp path disguised as.cache<hex> or dotnet_diag_<hex>.exe, chmod 0755, and spawned detached via /bin/sh -c or cmd.exe with unref(). Destination hostnames are assembled from split string arrays (e.g. ['oob','-worker','.cf103-',...].join('')) and require('child_process') is masked as require('child_'+'process'). A cache-stamp file is written under a benign '.analytics_state' name. The behavior fires on module load, giving any consumer that requires this package a fetch-and-execute of opaque attacker-controlled native code.

Malicious versions

1 flagged

35.3.8

Indicators of compromise (SHA-256)

b6afd966a220b14c0d01a2132af36d206eee200ab806d61443b66379e560b324

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-block-visibility (version 35.3.8). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging claims-block-visibility across your stack and pipelines.
If you installed it — respond
Remove claims-block-visibility 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-block-visibility 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-block-visibility 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-block-visibility on npm has been identified as a malicious package (version 35.3.8 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

IN-MAL-2026-015169

References

npmjs.com

Credits

Amazon Inspector · finder

Detect & block this

O3 blocks claims-block-visibility-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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