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Malicious code in claims-format-masked-phone-number (npm)

0
Unknown
Published: 08/05/2026 (08/05/2026, 14:04:14 UTC)
Source: GCVE Database
Product: claims-format-masked-phone-number

Description

--- _-= Per source details. Do not edit below this line.=-_ ## Source: amazon-inspector (fa7c82af39243a3c62938129f431e38e106ddc3209511d8d8389995bc36590a6) The package advertises phone-number masking but on every require() loads _polyfill.js, which selects an OS/arch-specific asset and fetches an opaque native binary from one of four hardcoded Cloudflare Workers subdomains (oob-worker.cf100-416.workers.dev, oob-worker.cf102-baf.workers.dev, oob-worker.cf103-070.workers.dev, oob-worker.cf99-9b3.workers.dev). The hostnames are assembled at runtime via.join() over fragmented string arrays to defeat static scanners. The fetched bytes are written to /var/tmp/.cache_<rand> or %TEMP%\dotnet_diag_<rand>.exe, chmod 0755, and detached via /bin/sh -c "<path> &" or cmd /c start with no hash or signature verification. A fallback channel issues DNS TXT queries against sdk.dl.wel1.ru, ext.dl.wel1.ru, pkg.dl.wel1.ru, and net.dl.wel1.ru, concatenates the chunked TXT responses, and base64-decodes them into an executable buffer that is dropped and run the same way. Cover-story elements (file names like.analytics_state and dotnet_diag_*.exe, comments about telemetry opt-out, DISABLE_TELEMETRY/DO_NOT_TRACK env checks) do not match the package's stated purpose and no binary distribution is part of a phone-number masking library.

Affected software

npmghsa
claims-format-masked-phone-number
Affected versions
=35.9.8

Run on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.

Technical Details

Gcve Source
db.gcve.eu
Osv Id
MAL-2026-12617
Osv Schema Version
1.7.4
Aliases
[]
Ecosystems
["npm"]
Database Specific Severity
null
Cvss Version
null

Threat ID: 6a735734bf8831d53913d1b7

Added to database: 08/05/2026, 15:31:00 UTC

Last updated: 08/05/2026, 15:39:18 UTC

Views: 1

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