The malicious code in @years20/[email protected] executes on npm install (postinstall) and on require/import of the package's main entry files (callback.js and index.js). It runs system commands to gather user ID, hostname, and WSL detection, reads the SSH Ed25519 public key, base64-encodes this data, and sends it via an unverified TLS GET request to a remote URL. The payload is structured as a shell command that can be replayed by a command and control server. The scripts also write an embedded base64 OpenSSH Ed25519 private key to /tmp/pk with restrictive permissions and attempt SSH authentication to localhost on ports 22495 and 22 using a list of common usernames, aiming to find pre-configured SSH access on developer and CI machines. This ensures execution even if npm install is run with --ignore-scripts, as the package is loaded at runtime by n8n.

This malicious package can exfiltrate sensitive system and SSH key information to an attacker-controlled server, potentially compromising system confidentiality. The embedded private key and SSH brute force attempts to localhost allow the attacker to gain unauthorized access to local services, enabling lateral movement or persistence on developer and CI hosts. The disabling of TLS verification increases the risk of man-in-the-middle interception during data exfiltration. Overall, this poses a significant risk to the integrity and confidentiality of affected systems.

No official patch or remediation is currently documented for this malicious package. Users should immediately remove @years20/n8n-nodes-utils-helper-b version 1.0.0 from their environments and avoid installing or importing this package. Verify that no unauthorized SSH keys have been added to /tmp or other locations and audit local SSH access logs for suspicious activity. Consider rotating SSH keys and credentials if this package was installed. Monitor for any unexpected network connections to the indicated remote domain. Since this is a malicious package, remediation involves removal and incident response rather than patching.