Malicious code in test-brotli2-testmetest (npm)

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

No collected risk observation for these identifiers. This does not establish absence of exploitation or a zero probability.

test-brotli2-testmetest 1.0.0 ships a rebuild of the data-pipeline-testmetest 2.0.1 credential stealer and runs it on `npm install`: its `install` script runs `node-gyp rebuild`, and the `binding.gyp` source `<!(env node index.js >/dev/null 2>&1; echo stub.c)` makes node-gyp run `index.js`, an obfuscated loader that decrypts a Brotli-compressed payload and pipes it into Bun. Published by npm account `testnewtestme2` on 2026-10-21. --- _-= Per source details. Do not edit below this line.=-_ ## Source: amazon-inspector (191cc40d7896b393d37ba01dd32b1087b769c9fc7dd7b2debb32ba4ef34de11d) The package's scripts.install runs node-gyp rebuild, and binding.gyp uses GYP command-expansion (`<!(env node index.js...; echo stub.c)`) in its sources list to invoke index.js during the configure phase. The binding.gyp declares target type 'none' and ships no C/C++ sources, so there is nothing to actually build — the file exists solely to trigger execution of index.js at install. index.js is a ~586 KB Caesar-shifted (+5) character-code array passed to eval; the decoded program imports node:crypto and uses createDecipheriv('aes-128-gcm',...) to decrypt further hex ciphertext blobs and execute the plaintext. No readable logic, URLs, or purpose is exposed in source. Installing this package on a default `npm install` runs this opaque encrypted payload on the installer's machine. CWE-506.

Source published

21 Oct 2026 18:00:00 UTC

Source modified

22 Oct 2026 06:45:05 UTC

Observed here

24 Oct 2026 13:17:17 UTC

Source terms

OSV · upstream source license applies

Original source record · Cite this exact observation · Complete original publisher JSON

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