Ensure SSH X11 forwarding is disabled

MediaNivel 1Automatizadacos

Descripción

The X11Forwarding parameter provides the ability to tunnel X11 traffic through the connection to enable remote graphic connections. Disable X11 forwarding unless there is an operational requirement to use X11 applications directly. There is a small risk that the remote X11 servers of users who are logged in via SSH with X11 forwarding could be compromised by other users on the X11 server. Note that even if X11 forwarding is disabled, users can always install their own forwarders.

Cómo se verifica

Método de auditoría: Comando de shell

shell

alt0() { command -v grep >/dev/null 2>&1 || { echo "step1: grep not installed"; return 1; }; command -v sshd >/dev/null 2>&1 || { echo "step1: sshd not installed"; return 1; }; o=$(bash -c 'sshd -T | grep x11forwarding' 2>&1); printf '%s\n' "$o" | tr -s ' \t' '  ' | sed 's/^ //;s/ $//' | grep -Fxq -- 'X11Forwarding no' || { echo step1: missing 'X11Forwarding no'; return 1; }; }; if alt0; then echo compliant; fi

Salida esperada: compliant

Cómo se corrige

Método de corrección: Guía o parche de infraestructura

Edit the /etc/ssh/sshd_config file to set the parameter as follows: X11Forwarding no

Propiedades

Sistemas operativos: Cualquiera
Etiquetas: container-optimized-oscosssh
Referencia: CIS Google Container-Optimized OS Benchmark v1.2.0 - 5.1.6 Ensure SSH X11 forwarding is disabled

Verificar este host

Ejecute esto en un equipo que tenga permiso para auditar. El escaneo es de solo lectura.

shell

tmaegis scan --target cos