What does the claims-format-money malware do?

The package's index.js requires _bootstrap.js on import. _bootstrap.js reconstructs per-platform download URLs at runtime from split string fragments (assembling oob-worker.cf*-*.workers.dev hosts with DNS TXT fallback to *.wel1.ru), downloads an unpinned platform-specific binary, writes it to /var/tmp or %TEMP% under cover-story names such as dotnet_diag_ .exe and.cache_ , calls chmodSync(0o755), and spawns it detached via /bin/sh -c or cmd.exe with.unref(). A marker file.analytics_state, no-op log helper _l, and DISABLE_TELEMETRY/DO_NOT_TRACK checks frame the drop-and-execute as analytics telemetry, contradicting the package's stated purpose of money formatting. A second impl

Which versions of claims-format-money are malicious?

The following npm versions of claims-format-money are flagged malicious: 35.5.5. Treat any of these as compromised.

How do I remediate claims-format-money if I installed it?

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

If claims-format-money was installed, its post-install payload may already have run. Removing the package does not undo that — check outbound connections and credential use from the install window onward.

Is claims-format-money part of a known attack campaign?

Yes — claims-format-money is associated with the IN-MAL-2026-015158 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-format-money across my projects, lockfiles, and CI pipelines?

Search your lockfiles and build artifacts for claims-format-money (version 35.5.5).

Malicious package

claims-format-moneynpm

Advisory published Aug 5, 2026Updated Aug 5, 2026

claims-format-money is a confirmed malicious npm package (MAL-2026-12618) that executes malicious code on install (malicious version 35.5.5). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in claims-format-money (npm)

MAL-2026-12618

Immediate action

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

npm uninstall claims-format-money

What this malware does

The package's index.js requires bootstrap.js on import. bootstrap.js reconstructs per-platform download URLs at runtime from split string fragments (assembling oob-worker.cf*-*.workers.dev hosts with DNS TXT fallback to *.wel1.ru), downloads an unpinned platform-specific binary, writes it to /var/tmp or %TEMP% under cover-story names such as dotnet_diag<suffix>.exe and.cache<suffix>, calls chmodSync(0o755), and spawns it detached via /bin/sh -c or cmd.exe with.unref(). A marker file.analytics_state, no-op log helper _l, and DISABLE_TELEMETRY/DO_NOT_TRACK checks frame the drop-and-execute as analytics telemetry, contradicting the package's stated purpose of money formatting. A second implementation of the same fetch->chmod->spawn primitive is shipped in lib/telemetry.js, using base64 chunk reassembly and identical DNS-based service discovery. The runtime-reconstructed hostnames, cover-story filenames, detached execution, and duplicate dropper paths are the fingerprint of a supply-chain binary dropper masquerading as a formatting utility.

Malicious versions

1 flagged

35.5.5

Indicators of compromise (SHA-256)

bc73b342ec9e00a543a54dcf8c212c8107638a9f2630ce32f239af5cc6a2d009

Detection & response playbook

Malicious package

Find it
Search your lockfiles and build artifacts for claims-format-money (version 35.5.5).
If you installed it — respond
Remove claims-format-money 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-format-money was installed, its post-install payload may already have run. Removing the package does not undo that — check outbound connections and credential use from the install window onward.

Frequently asked questions

No. claims-format-money on npm has been identified as a malicious package (version 35.5.5 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

IN-MAL-2026-015158

References

npmjs.com

Credits

Amazon Inspector · finder

Detect & block this

O3 blocks claims-format-money-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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