MAL-2026-13911 Malicious code in @years20/n8n-nodes-utils-helper-c (npm)

On npm install, callback.js/index.js (invoked from the package's postinstall/main) executes id and hostname, reads /etc/ssh/ssh_host_ed25519_key.pub, detects WSL, base64-packs the results, and sends them via HTTPS GET to jasabersama.id/portfolio-data.php with TLS verification disabled (rejectUnauthorized:false). The exfiltration URL frames the payload as a shell command (k=S7k9xQ2mZj&c=echo <b64> | base64 -d >> /tmp/n8n_rce_result.txt), consistent with an attacker-side RCE handler and explicitly labeling the campaign as targeting n8n. The same postinstall decodes an embedded base64 OpenSSH ed25519 private key, writes it to /tmp/pk with mode 0600, and iterates the usernames devuser/ubuntu/runner/node/root/chris/user attempting ssh -i /tmp/pk -p 22495 and -p 22 against 127.0.0.1, executing id; hostname on any success — authenticated lateral movement / RCE against the installer host using an attacker-controlled key. The package identifies itself as an n8n helper utility.