Ensure access to SSH private host key files is configured

MittelStufe 1Automatisiertlinux

Beschreibung

An SSH private key is one of two files used in SSH public key authentication. In this authentication method, the possession of the private key is proof of identity. Only a private key that corresponds to a public key will be able to authenticate successfully. The private keys need to be stored and handled carefully, and no copies of the private key should be distributed.

So wird geprüft

Prüfmethode: Shell-Befehl

shell

alt0() { o=$(bash -c '#!/usr/bin/env bash
{
   l_ssh_group=""
   grep -Psiq -- '"'"'^\h*ID_LIKE="?([^#\n\r]+)?\bfedora\b'"'"' /etc/os-release 2>/dev/null && \
      grep -Psq -- '"'"'^ssh_keys\b'"'"' /etc/group 2>/dev/null && l_ssh_group="ssh_keys"
   while IFS= read -r l_file; do
      ssh-keygen -lf "$l_file" &>/dev/null || continue
      while IFS=: read -r l_mode l_owner l_group; do
         [ "$l_group" = "$l_ssh_group" ] && l_mask="0137" || l_mask="0177"
         if [ $(( l_mode & l_mask )) -gt 0 ] || [ "$l_owner" != "root" ] || \
            { [ "$l_group" != "$l_ssh_group" ] && [ "$l_group" != "root" ];
}; then
            printf '"'"'%s\n'"'"' "\"$l_file\": mode $l_mode owner $l_owner group $l_group"
         fi
      done < <(stat -Lc '"'"'%#a:%U:%G'"'"' "$l_file")
   done < <(sshd -T 2>/dev/null | awk '"'"'$1=="hostkey"{print $2}'"'"')
}' 2>&1); [ -z "$o" ] || { echo "step1: $o" | head -c 300; return 1; }; }; if alt0; then echo compliant; fi

Erwartete Ausgabe: compliant

So wird behoben

Behebungsmethode: Anleitung oder Infrastruktur-Patch

Run the following script to set the owner and restrict permissions on each SSH private host key file from the running sshd configuration: #!/usr/bin/env bash { while IFS= read -r l_file; do ssh-keygen -lf "$l_file" &>/dev/null || continue chown root:root "$l_file" chmod u-x,go-rwx "$l_file" done < <(sshd -T 2>/dev/null | awk '$1=="hostkey"{print $2}') } • OR - Where host-based authentication requires the ssh_keys group to read the host keys, set group ownership to ssh_keys with mode 0640 or more restrictive instead: #!/usr/bin/env bash { while IFS= read -r l_file; do ssh-keygen -lf "$l_file" &>/dev/null || continue chown root:ssh_keys "$l_file" chmod u-x,g-wx,o-rwx "$l_file" done < <(sshd -T…

Eigenschaften

Betriebssysteme: rocky-9
Tags: cis-convertedlinux
Referenz: CIS Rocky Linux 9 Benchmark v3.0.0 - 5.1.3

Diesen Host prüfen

Führen Sie dies auf einem Rechner aus, den Sie prüfen dürfen. Der Scan ist schreibgeschützt.

shell

tmaegis scan --target linux