net-codec-testmetestnpm
Advisory published Updated
net-codec-testmetest is a confirmed malicious npm package (MAL-2026-18186) that executes malicious code on install (malicious version 1.0.1). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in net-codec-testmetest (npm)
What this malware does
The package has no native source files but ships a binding.gyp whose sole target is type:'none' and whose sources array uses GYP command expansion (<!(env node index.js...)) to execute index.js during node-gyp rebuild, which npm invokes automatically whenever a binding.gyp is present. index.js is a Caesar-cipher-obfuscated IIFE whose decoded body imports node:crypto, reads the shipped data.bin blob, AES-128-GCM-decrypts it with hardcoded key/iv/aad, brotli-decompresses the result into a temporary file, and spawns that file under the Bun runtime (declared as the package's only dependency). The combination — binding.gyp with no native sources used purely as an install-time execution smuggler, an obfuscated eval-based loader, and an opaque encrypted payload executed under an alternate runtime — is a packed dropper with no legitimate function for a stated utility library.
Malicious versions
Indicators of compromise (SHA-256)
Detection & response playbook
Malicious packageFind it
Search your lockfiles and build artifacts for net-codec-testmetest (version 1.0.1).
If you installed it — respond
Remove net-codec-testmetest 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 net-codec-testmetest 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
Campaign
References
Credits
- Amazon Inspector · finder
Detect & block this
O3 blocks net-codec-testmetest-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.