TMA-BIND-5.2

Securely Authenticate Dynamic Updates

MediaNivel 1Automatizadabind

Descripción

Dynamic updates are used to automate the updating of zones. Dynamic updates are typically used with DHCP; however, updates may include other records. The allow-update option allows deleting or adding any resource records of a zone except the SOA and NS records, and should not be used. The audit requires every allow-update list to contain only none or localhost and no update-policy to reference IP addresses. The audit parses the effective configuration printed by named-checkconf -p (all include files resolved) from /etc/named.conf (RHEL; chroot /var/named/chroot is detected) or /etc/bind/named.conf (Debian/Ubuntu).

Cómo se verifica

Método de auditoría: Comando de shell

shell

if [ -f /var/named/chroot/etc/named.conf ]; then out=$(named-checkconf -t /var/named/chroot -p /etc/named.conf 2>/dev/null) || exit 1
else conf=/etc/named.conf; [ -f "$conf" ] || conf=/etc/bind/named.conf
  out=$(named-checkconf -p "$conf" 2>/dev/null) || exit 1; fi
flat=$(printf '%s\n' "$out" | tr '\t\n' '  ' | tr -s ' ')
opts=$(printf '%s\n' "$out" | awk '/^options[ \t]*\{/{f=1} f{print} f&&/^\};/{exit}' | tr '\t\n' '  ' | tr -s ' ')
bad=$(printf '%s\n' "$flat" | grep -Eo '(^|[ ;{])allow-update \{[^}]*\}' | sed 's/.*allow-update {//; s/}$//' | tr ';' '\n' | sed 's/^ *//; s/ *$//' | grep -v '^$' | grep -Eiv '^("?none"?|"?localhost"?)$')
ip=$(printf '%s\n' "$flat" | grep -Eo 'update-policy \{[^}]*\}' | grep -Eo '[0-9]+\.[0-9]+\.[0-9]+\.[0-9]+(/[0-9]+)?')
[ -n "$ip" ] && bad="$bad update-policy uses addresses: $ip"
[ -z "$bad" ] && echo compliant || { echo 'allow-update entries not allowed:'; printf '%s\n' "$bad" | sort -u; }

Salida esperada: compliant

Cómo se corrige

Método de corrección: Guía o parche de infraestructura

Perform the following steps for remediation: ; Remove any allow-update options from the global options configuration. ; Replace or add allow-update options to the zone files to specify a securely generated TSIG or SIG(0) key identifier, along with the appropriate domain or sub- domain, and the appropriate resource record type.

Propiedades

Sistemas operativos: Cualquiera
Etiquetas: binddnszone-transfer
Referencia: CIS ISC BIND DNS Server 9.11 Benchmark v1.0.0 - 5.2 Securely Authenticate Dynamic Updates

Verificar este host

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

shell

tmaegis scan --target bind