claims-auth-api-adaptersnpm
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)
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
Indicators of compromise (SHA-256)
Detection & response playbook
Malicious packageFind it
Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for claims-auth-api-adapters (version 35.3.3). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging claims-auth-api-adapters across your stack and pipelines.
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.
Did it already run?
If claims-auth-api-adapters 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-auth-api-adapters 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
Campaign
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.