pure-folder-threenpm
pure-folder-three is a confirmed malicious npm package (MAL-2026-10218) that executes malicious code on install (malicious versions 0.5.0, 0.6.0, 0.7.0…). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in pure-folder-three (npm)
What this malware does
[email protected] executes attacker-controlled shell commands on install and on import. The postinstall entry (src/build.js) decodes an obfuscated destination via base-45/base-77 fromCharCode arithmetic, resolving to https://rnjkerbf.org/T/ with process.platform appended, and dynamically resolves require('https') through the same decoder. It issues an https request to that host and passes the response's m header directly to child_process.execSync, giving the remote server arbitrary command execution on the installer host. The payload is gated by a username check that skips execution when USER/LOGNAME/USERNAME contains 'justin', excluding the author's own machine while running on every other installer. The same chain is also reachable at require/import time: src/index.js imports './build.js' from the package main, so consumers that load the module trigger the fetch-and-exec chain even with npm install --ignore-scripts. The URL, hostname, and the 'https' module name are all reconstructed from numeric arrays, concealing the network destination and the execution sink.
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.
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 pure-folder-three (5 malicious versions). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging pure-folder-three across your stack and pipelines.
If you installed it — respond
Remove pure-folder-three 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 pure-folder-three 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 pure-folder-three 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 pure-folder-three-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.