MAL-2026-18333: Malicious code in path-stream-utils-testmetest (npm)

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Source: amazon-inspector (64a028e4ea3039755f4b18b003e2d9722722ca96c51652674dd1bb27f375e4d0) The package self-describes as a 'Temporary package placeholder for staged publishing' (package.json stub:true, README 'Temporary Holding Version') but ships a Linux addon.node, a Windows.node, and a 6,052,359-byte opaque.napicache blob containing no printable strings. package.json defines a postinstall that executes node -e "require('./addon.node').init()", and index.js requires and invokes the same init(). On invocation the native addon reads the sibling.napicache file (format string '%s/.napicache'), writes the bytes to a PID-named hidden file under /tmp (format '/tmp/.%u'), chmods it executable, and detaches a child via fork+setsid+execlp, so the opaque payload runs under the installer's user on npm install and on every require() of the package. Before executing the dropped file the addon enumerates CI and sandbox indicators (GITHUBACTIONS, GITLABCI, TRAVIS, CIRCLECI, SANDBOX, JENKINSURL, BUILDKITE, CODEBUILDBUILDID, APPVEYOR, SEMAPHORE, TEAMCITYVERSION, BITBUCKETBUILDNUMBER, NETLIFY, VERCEL, CFBUILDID, SCREWDRIVER), reads /proc/1/cgroup and /proc/1/cmdline for container markers (docker, containerd, kubepod, sandbox, podman), and inspects /proc/self/status for TracerPid, gating execution to non-analysis hosts. The payload bytes themselves are packed/encrypted and not inspectable from the tarball. A placeholder stub has no legitimate reason to ship a native dropper, detach a hidden /tmp child, and evade sandboxes.

Source: ghsa-malware (910dd2c3846dd989ee98147187c379760a3d055ffe413f85d36def235d6a7cf7) Any computer that has this package installed or running should be considered fully compromised. All secrets and keys stored on that computer should be rotated immediately from a different computer. The package should be removed, but as full control of the computer may have been given to an outside entity, there is no guarantee that removing the package will remove all malicious software resulting from installing it.