Ensure permissions on SSH private host key files are configured

MoyenneNiveau 1Automatiséelinux

Description

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.

Méthode de vérification

Méthode d'audit: Commande shell

shell

alt0() { o=$(bash -c 'find /etc/ssh -xdev -type f -name '"'"'ssh_host_*_key'"'"' -exec stat {} \;' 2>&1); printf '%s\n' "$o" | tr -s ' \t' '  ' | sed 's/^ //;s/ $//' | grep -Fxq -- 'File: ‘/etc/ssh/ssh_host_rsa_key’' || { echo step1: missing 'File: ‘/etc/ssh/ssh_host_rsa_key’'; return 1; }; printf '%s\n' "$o" | tr -s ' \t' '  ' | sed 's/^ //;s/ $//' | grep -Fxq -- 'Size: 1679 Blocks: 8 IO Block: 4096 regular file' || { echo step1: missing 'Size: 1679 Blocks: 8 IO Block: 4096 regular file'; return 1; }; printf '%s\n' "$o" | tr -s ' \t' '  ' | sed 's/^ //;s/ $//' | grep -Fxq -- 'Device: ca01h/51713d Inode: 8628138 Links: 1' || { echo step1: missing 'Device: ca01h/51713d Inode: 8628138 Links: 1'; return 1; }; printf '%s\n' "$o" | tr -s ' \t' '  ' | sed 's/^ //;s/ $//' | grep -Fxq -- 'Access: (0640/-rw-r-----) Uid: ( 0/ root) Gid: ( 998/ssh_keys)' || { echo step1: missing 'Access: (0640/-rw-r-----) Uid: ( 0/ root) Gid: ( 998/ssh_key'; return 1; }; printf '%s\n' "$o" | tr -s ' \t' '  ' | sed 's/^ //;s/ $//' | grep -Fxq -- 'Access: 2018-10-22 18:24:56.861750616 +0000' || { echo step1: missing 'Access: 2018-10-22 18:24:56.861750616 +0000'; return 1; }; printf '%s\n' "$o" | tr -s ' \t' '  ' | sed 's/^ //;s/ $//' | grep -Fxq -- 'Modify: 2018-10-22 18:24:56.861750616 +0000' || { echo step1: missing 'Modify: 2018-10-22 18:24:56.861750616 +0000'; return 1; }; printf '%s\n' "$o" | tr -s ' \t' '  ' | sed 's/^ //;s/ $//' | grep -Fxq -- 'Change: 2018-10-22 18:24:56.873750616 +0000' || { echo step1: missing 'Change: 2018-10-22 18:24:56.873750616 +0000'; return 1; }; printf '%s\n' "$o" | tr -s ' \t' '  ' | sed 's/^ //;s/ $//' | grep -Fxq -- 'Birth: -' || { echo step1: missing 'Birth: -'; return 1; }; printf '%s\n' "$o" | tr -s ' \t' '  ' | sed 's/^ //;s/ $//' | grep -Fxq -- 'File: ‘/etc/ssh/ssh_host_ecdsa_key’' || { echo step1: missing 'File: ‘/etc/ssh/ssh_host_ecdsa_key’'; return 1; }; printf '%s\n' "$o" | tr -s ' \t' '  ' | sed 's/^ //;s/ $//' | grep -Fxq -- 'Size: 227 Blocks: 8 IO Block: 4096 regular file' || { echo step1: missing 'Size: 227 Blocks: 8 IO Block: 4096 regular file'; return 1; }; printf '%s\n' "$o" | tr -s ' \t' '  ' | sed 's/^ //;s/ $//' | grep -Fxq -- 'Device: ca01h/51713d Inode: 8631760 Links: 1' || { echo step1: missing 'Device: ca01h/51713d Inode: 8631760 Links: 1'; return 1; }; printf '%s\n' "$o" | tr -s ' \t' '  ' | sed 's/^ //;s/ $//' | grep -Fxq -- 'Access: (0640/-rw-r-----) Uid: ( 0/ root) Gid: ( 998/ssh_keys)' || { echo step1: missing 'Access: (0640/-rw-r-----) Uid: ( 0/ root) Gid: ( 998/ssh_key'; return 1; }; printf '%s\n' "$o" | tr -s ' \t' '  ' | sed 's/^ //;s/ $//' | grep -Fxq -- 'Access: 2018-10-22 18:24:56.897750616 +0000' || { echo step1: missing 'Access: 2018-10-22 18:24:56.897750616 +0000'; return 1; }; printf '%s\n' "$o" | tr -s ' \t' '  ' | sed 's/^ //;s/ $//' | grep -Fxq -- 'Modify: 2018-10-22 18:24:56.897750616 +0000' || { echo step1: missing 'Modify: 2018-10-22 18:24:56.897750616 +0000'; return 1; }; printf '%s\n' "$o" | tr -s ' \t' '  ' | sed 's/^ //;s/ $//' | grep -Fxq -- 'Change: 2018-10-22 18:24:56.905750616 +0000' || { echo step1: missing 'Change: 2018-10-22 18:24:56.905750616 +0000'; return 1; }; printf '%s\n' "$o" | tr -s ' \t' '  ' | sed 's/^ //;s/ $//' | grep -Fxq -- 'Birth: -' || { echo step1: missing 'Birth: -'; return 1; }; printf '%s\n' "$o" | tr -s ' \t' '  ' | sed 's/^ //;s/ $//' | grep -Fxq -- 'File: ‘/etc/ssh/ssh_host_ed25519_key’' || { echo step1: missing 'File: ‘/etc/ssh/ssh_host_ed25519_key’'; return 1; }; printf '%s\n' "$o" | tr -s ' \t' '  ' | sed 's/^ //;s/ $//' | grep -Fxq -- 'Size: 387 Blocks: 8 IO Block: 4096 regular file' || { echo step1: missing 'Size: 387 Blocks: 8 IO Block: 4096 regular file'; return 1; }; printf '%s\n' "$o" | tr -s ' \t' '  ' | sed 's/^ //;s/ $//' | grep -Fxq -- 'Device: ca01h/51713d Inode: 8631762 Links: 1' || { echo step1: missing 'Device: ca01h/51713d Inode: 8631762 Links: 1'; return 1; }; printf '%s\n' "$o" | tr -s ' \t' '  ' | sed 's/^ //;s/ $//' | grep -Fxq -- 'Access: (0600/-rw-------) Uid: ( 0/ root) Gid: ( 998/ssh_keys)' || { echo step1: missing 'Access: (0600/-rw-------) Uid: ( 0/ root) Gid: ( 998/ssh_key'; return 1; }; }; if alt0; then echo compliant; fi

Sortie attendue: compliant

Méthode de correction

Méthode de correction: Recommandation ou correctif d'infrastructure

Run the following commands to set ownership and permissions on the private SSH host key files # find /etc/ssh -xdev -type f -name 'ssh_host_*_key' -exec chown root:ssh_keys {} \; # find /etc/ssh -xdev -type f -name 'ssh_host_*_key' -exec chmod 0640 {} \;

Propriétés

Systèmes d'exploitation: alinux-2
Étiquettes: cis-convertedlinux
Référence: CIS Aliyun Linux 2 Benchmark v1.0.0 ARCHIVE - 5.2.3

Vérifier cet hôte

Exécutez cette commande sur une machine que vous êtes autorisé à auditer. L'analyse est en lecture seule.

shell

tmaegis scan --target linux