Ensure access to SSH public host key files is configured

SedangLevel 1Otomatislinux

Deskripsi

An SSH public key is one of two files used in SSH public key authentication. In this authentication method, a public key is a key that can be used for verifying digital signatures generated using a corresponding private key. Only a public key that corresponds to a private key will be able to authenticate successfully.

Cara pemeriksaan

Metode audit: Perintah shell

shell

alt0() { o=$(bash -c '#!/usr/bin/env bash
{
   l_ssh_group=""
   grep -Psiq -- '"'"'^\h*ID_LIKE="?([^#\n\r]+)?\bfedora\b'"'"' /etc/os-release 2>/dev/null && \
      grep -Psq -- '"'"'^ssh_keys\b'"'"' /etc/group 2>/dev/null && l_ssh_group="ssh_keys"
   while IFS= read -r l_key; do
      l_file="${l_key}.pub"
      ssh-keygen -lf "$l_file" &>/dev/null || continue
      while IFS=: read -r l_mode l_owner l_group; do
         if [ $(( l_mode & 0133 )) -gt 0 ] || [ "$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

Output yang diharapkan: compliant

Cara perbaikan

Metode perbaikan: Panduan atau patch infrastruktur

Run the following script to set the owner, group, and restrict permissions on each SSH public host key file from the running sshd configuration: #!/usr/bin/env bash { while IFS= read -r l_key; do l_file="${l_key}.pub" [ -e "$l_file" ] || continue chown root:root "$l_file" chmod u-x,go-wx "$l_file" done < <(sshd -T 2>/dev/null | awk '$1=="hostkey"{print $2}') }

Properti

Sistem operasi: almalinux-9
Tag: cis-convertedlinux
Referensi: CIS AlmaLinux OS 9 Benchmark v3.0.0 - 5.1.4

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shell

tmaegis scan --target linux