On Linux systems and supported network devices, Nessus uses Secure Shell (SSH) protocol version 2 based programs (e.g., OpenSSH, Solaris SSH, etc.) for host-based checks.

This mechanism encrypts the data in transit to protect it from being viewed by sniffer programs. Nessus supports five types of authentication methods for use with SSH: username and password, public/private keys, digital certificates, and Kerberos.

Users can select SSH settings from the Credentials menu and enter credentials for scanning Linux systems.

These credentials are used to obtain local information from remote Linux systems for patch auditing or compliance checks.

Note: Non-privileged users with local access on Linux systems can determine basic security issues, such as patch levels or entries in the /etc/passwd file. For more comprehensive information, such as system configuration data or file permissions across the entire system, an account with root privileges is required