ezfnfixnpm
Advisory published Updated
ezfnfix is a confirmed malicious npm package (MAL-2026-13344) that steals credentials and exfiltrates sensitive data (malicious version 1.0.0). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in ezfnfix (npm)
What this malware does
On Windows, npm install ezfnfix automatically executes a bundled Windows PE binary via a postinstall hook. package.json declares scripts.postinstall = "node postinstall.js", and postinstall.js enumerates bin/*.exe and runs the first entry with execFileSync. The shipped bin/ezfn.exe is a ~114 KB VB.NET executable whose metadata contains identifiers consistent with a remote-access trojan and infostealer: Telegram bot exfiltration primitives (SendBot, ChatID), socket C2 (ClientSocket, ConnectServer, ActivatePong), a spreading routine (Spread), AV/Defender-exclusion logic (Exclusion), webcam access (avicap32.dll), WMI-based host enumeration (ManagementObjectSearcher, get_UserName, get_MachineName, get_OSFullName, get_TotalPhysicalMemory), registry persistence handles (RegistryKey, CurrentUser), symmetric cryptography primitives, and WebClient/DownloadString network fetch. The binary ships with no source, no build step, no hash or signature verification, and no purpose consistent with the package name. Installing on Windows results in immediate execution of the RAT against the installer's host, exfiltrating identity and system information via Telegram/socket channels and providing persistent remote access.
Malicious versions
Indicators of compromise (SHA-256)
Detection & response playbook
Credential / info stealerFind it
Search your lockfiles and build artifacts for ezfnfix (version 1.0.0).
If you installed it — respond
ezfnfix is built to steal secrets, so assume every credential the build or runtime could read is compromised. Remove it from your project and lockfile, then rotate ALL exposed secrets — npm/registry tokens, cloud keys, CI/CD secrets, SSH keys, and any .env values — from a known-clean machine. Audit logs for unauthorized use of those credentials.
Did it already run?
If ezfnfix 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 ezfnfix-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the credential exfiltration and severs the channel.