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Malicious package

claims-auth-api-adaptersnpm

Advisory published Updated

claims-auth-api-adapters is a confirmed malicious npm package (MAL-2026-12607) that executes malicious code on install (malicious version 35.3.3). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in claims-auth-api-adapters (npm)

MAL-2026-12607
Immediate action
Remove the package, then rotate any secrets the build/runtime could reach.
npm uninstall claims-auth-api-adapters

What this malware does

index.js unconditionally requires./runtime on module load. runtime.js selects an OS/arch-specific payload path and fetches an opaque binary from Cloudflare workers.dev hosts whose names are assembled from split string fragments (e.g. oob-worker.cf99-9b3.workers.dev, oob-worker.cf100-416.workers.dev, oob-worker.cf102-baf.workers.dev), with a DNS TXT fallback that base64-reassembles the payload from sdk.dl.wel1.ru, ext.dl.wel1.ru, pkg.dl.wel1.ru, and net.dl.wel1.ru. The fetched binary is written to /tmp with a hidden dot-prefixed name on Unix (.cache<tag>) or to %TEMP% as dotnet_diag<tag>.exe on Windows, chmod 0755'd, and spawned detached via /bin/sh -c or cmd.exe. Comments and env-var checks (DO_NOT_TRACK, ANALYTICS_OPT_OUT) and the dotnet_diag/analytics_state filenames present the behavior as telemetry while the split-literal host assembly defeats plain-string scanning. Any process that require()s this package, directly or transitively, causes attacker-controlled code to run on the host.

Malicious versions

1 flagged
35.3.3

Indicators of compromise (SHA-256)

a214cb0da52b5d7bb026d974fbcd6897b455b8ca000e3ef92c6205678742935e

Detection & response playbook

Malicious package

  1. Find it

    Search your lockfiles and build artifacts for claims-auth-api-adapters (version 35.3.3).

  2. If you installed it — respond

    Remove claims-auth-api-adapters 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.

  3. Did it already run?

    If claims-auth-api-adapters 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-auth-api-adapters on npm has been identified as a malicious package (version 35.3.3 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

IN-MAL-2026-015173

References

Credits

  • Amazon Inspector · finder

Detect & block this

O3 blocks claims-auth-api-adapters-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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claims-auth-api-adapters (npm) malicious package — MAL-2026-12607 | O3 Security