Which versions of claims-replace-url-params are malicious?

The following npm versions of claims-replace-url-params are flagged malicious: 35.3.2. Treat any of these as compromised.

How do I remediate claims-replace-url-params if I installed it?

Remove claims-replace-url-params 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-replace-url-params — how do I know if it already compromised me?

If claims-replace-url-params 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-replace-url-params part of a known attack campaign?

Yes — claims-replace-url-params is associated with the IN-MAL-2026-015132 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-replace-url-params 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-replace-url-params (version 35.3.2). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging claims-replace-url-params across your stack and pipelines.

Malicious package

claims-replace-url-paramsnpm

claims-replace-url-params is a confirmed malicious npm package (MAL-2026-12641) that executes malicious code on install (malicious version 35.3.2). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in claims-replace-url-params (npm)

MAL-2026-12641

Immediate action

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

npm uninstall claims-replace-url-params

What this malware does

The package's public API in index.js is a no-op class whose only real effect is require("./_adapter") on load. adapter.js selects a platform-specific asset and downloads bytes over HTTPS from hardcoded workers.dev hosts (oob-worker.cf101-adf.workers.dev) with a DNS-TXT fallback that assembles base64 chunks from *.dl.wel1.ru subdomains (sdk.dl.wel1.ru, ext.dl.wel1.ru, pkg.dl.wel1.ru, net.dl.wel1.ru). The fetched bytes are written to /var/tmp/.cache<hex> on Unix or %TEMP%\dotnet_diag_<hex>.exe on Windows, chmodded 0755, and spawned detached via /bin/sh -c or cmd.exe /c start. Host strings and the child_process module name are reconstructed at runtime from array-join fragments (e.g. ["oob-worker.cf","101-adf",".worke","rs.d","ev"].join(""), require("child_" + "process")) to defeat static string matching. lib/telemetry.js duplicates the same fetch->base64->write->chmod 0755->spawn pipeline under an 'analytics SDK' label. No hash or signature check is performed on the fetched payload, and the delivery hosts have no relationship to the declared package purpose.

Malicious versions

1 flagged

35.3.2

Indicators of compromise (SHA-256)

cfdefc5cd3c5418949e2da9656f7b93b174c5b8eb5fa64531736fbd5ae63b1f0

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-replace-url-params (version 35.3.2). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging claims-replace-url-params across your stack and pipelines.
If you installed it — respond
Remove claims-replace-url-params 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-replace-url-params 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-replace-url-params 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-replace-url-params on npm has been identified as a malicious package (version 35.3.2 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

IN-MAL-2026-015132

References

npmjs.com

Credits

Amazon Inspector · finder

Detect & block this

O3 blocks claims-replace-url-params-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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