The 'ref-slot' npm package version 1.0.9 includes a postinstall hook that runs a multi-stage malicious payload. First, it collects sensitive files from the user's home directory and Windows drive roots, including environment files, wallet keys, configuration files, and documents, uploading them to a remote server. Second, on Linux systems, it installs a persistent SSH backdoor by appending an attacker-supplied public key to authorized_keys, changing ownership of the .ssh directory, enabling the firewall, and allowing inbound SSH traffic, leveraging passwordless sudo privileges. Third, it fetches live scan and block patterns from the attacker's server to dynamically control what data is stolen. This results in full system compromise and persistent remote access.

Systems that install the affected package are fully compromised. Sensitive credentials and files are exfiltrated, and persistent remote access is established on Linux hosts with passwordless sudo. This compromises confidentiality, integrity, and availability of affected systems. Secret rotation is mandatory as attackers may have obtained all stored keys and credentials.

No official patch or fix is currently available. Immediate removal of the 'ref-slot' package version 1.0.9 is required. All secrets and credentials stored on the compromised system must be rotated from a separate, trusted device. Due to the persistent backdoor and full system compromise, a full system rebuild or forensic analysis is recommended to ensure removal of all malicious components.