TMA-BIND-5.1

Securely Authenticate Zone Transfers

HochStufe 2Automatisiertbind

Beschreibung

A zone transfer is a mechanism commonly used by DNS deployments to replicate zone information from master/primary servers to slave/secondary servers. Each pair of name servers participating in zone transfers should authenticate the requests and ensure the integrity of the responses by using a unique shared secret TSIG key. The audit requires at least one allow-transfer statement and that every allow-transfer list (options and zones) contains only none or key <name> entries; any, IP addresses and ACL names fail. 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).

So wird geprüft

Prüfmethode: Shell-Befehl

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 ' ')
printf '%s\n' "$flat" | grep -Eq '(^|[ ;{])allow-transfer \{' || { echo 'no allow-transfer statement'; exit 1; }
bad=$(printf '%s\n' "$flat" | grep -Eo '(^|[ ;{])allow-transfer \{[^}]*\}' | sed 's/.*allow-transfer {//; s/}$//' | tr ';' '\n' | sed 's/^ *//; s/ *$//' | grep -v '^$' | grep -Eiv '^("?none"?|key "?[^ "]+"?)$')
[ -z "$bad" ] && echo compliant || { echo 'allow-transfer entries not allowed:'; printf '%s\n' "$bad" | sort -u; }

Erwartete Ausgabe: compliant

So wird behoben

Behebungsmethode: Anleitung oder Infrastruktur-Patch

Generate TSIG keys 256 bits in length, unique for each host-to-host communication. Securely Transfer the keys and configure the keys to be required in all allow-transfer statements.

Eigenschaften

Betriebssysteme: Beliebig
Tags: binddnszone-transfer
Referenz: CIS ISC BIND DNS Server 9.11 Benchmark v1.0.0 - 5.1 Securely Authenticate Zone Transfers

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shell

tmaegis scan --target bind --level 2