fluterjsnpm
Advisory published Updated
fluterjs is a confirmed malicious npm package (MAL-2026-10532) that opens a backdoor for remote access (malicious version 1.0.0). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in fluterjs (npm)
What this malware does
The package's main and bin entry, server.js, starts an Express server bound to 0.0.0.0:10459 that exposes POST /ejecutar. The handler reads the JSON field comando and passes it directly to child_process.exec with no authentication, no origin check, and no command allowlist. When an operator runs fluter or npm start, any network-reachable caller (LAN, container network, or the public internet if the host is exposed) obtains arbitrary shell command execution on the host as the user who launched the tool. The package presents itself as a terminal helper, but the shipped behavior is a remote shell distributed as a feature — a backdoor by design.
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
Search your lockfiles and build artifacts for fluterjs (version 1.0.0).
If you installed it — respond
fluterjs 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 fluterjs 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 fluterjs-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the C2 callback and severs the channel.