node-denvnpm
node-denv is a confirmed malicious npm package (MAL-2026-5734) that opens a backdoor for remote access (malicious version 1.3.5). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in node-denv (npm)
What this malware does
node-denv presents itself as a pino-compatible logging middleware (index.js exports module.exports.pino = middleware and mimics pino's option shape including DEFAULT_LEVELS, formatters.bindings, redact, and customLevels). When a consumer instantiates the middleware, the package spawns a detached node lib/caller.js child process. lib/caller.js performs an HTTPS GET against https://jsonkeeper.com/b/EXSIF, reads the .cookie field from the JSON response, and passes it to new Function.constructor("require", s) invoked with the real require — granting the remotely-fetched JavaScript full Node.js capabilities (filesystem, network, child_process, env). The fetch is retried up to 5 times. A second jsonkeeper.com payload URL (https://jsonkeeper.com/b/ZK45J) is base64-encoded as DEV_API_KEY in lib/const.js as a fallback C2. jsonkeeper.com is an anonymous mutable JSON paste host — the attacker can change the executed payload at any time without republishing the package. The pino impersonation lures developers searching for the popular logger into installing this package, at which point any normal use triggers remote code execution on the installer's machine.
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
Backdoor / remote accessFind it
Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for node-denv (version 1.3.5). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging node-denv across your stack and pipelines.
If you installed it — respond
node-denv establishes remote access, so treat any host that installed it as fully compromised. Isolate the machine, remove the package, rotate all credentials it could reach, and rebuild from a trusted image rather than cleaning in place — a backdoor may have planted additional persistence.
Did it already run?
If node-denv 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 node-denv 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
- ReversingLabs · finder
Detect & block this
O3 blocks node-denv-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the C2 callback and severs the channel.