TMA-AIX-4.1.2.3

Ensure Home directory write access is restricted to owner

MoyenneNiveau 1Automatiséeaix

Description

Home directories must be writeable only by the owner. This recommendation audits (or removes) any write permission given via traditional file mode permissions (using chmod). Neither should a home directory have any permissions managed (whether permit or deny) via ACL's. HOME directories with group or world write access enable malicious users to add files or directories, or even remove them if the directory 'T' (SVTX) bit is not also set. Audit: HOME directories of uid >= 200 accounts must not be group or world writable (ACLs are not evaluated).

Méthode de vérification

Méthode d'audit: Commande shell

shell

command -v lsuser >/dev/null 2>&1 || exit 1; out=$( { lsuser -R files -a id home ALL | while read name ids homes rest; do uid=${ids#id=}; home=${homes#home=}; [ "$uid" -ge 200 ] 2>/dev/null || continue; [ "$home" = /dev/null ] && continue; [ "$home" = / ] && continue; if [ ! -d "$home" ]; then echo "$home does not exist ($name)"; continue; fi; ls -ld "$home/" | awk 'substr($1,6,1)=="w" || substr($1,9,1)=="w" {print "group/world writable: " $NF}'; done ; } 2>/dev/null ); [ -z "$out" ] && echo compliant || printf '%s\n' "$out" | head -n 20

Sortie attendue: compliant

Méthode de correction

Méthode de correction: Recommandation ou correctif d'infrastructure

For all local accounts with UID >= 200: Remove write permission from home directories that have group or world write access: #!/usr/bin/ksh -e # home_mode_acl: 4.8.1.3 # Provided to CIS by AIXTools # Copyright AIXTools, 2022 typeset -i UIDCK=$1 typeset -i ret=0 if test $UIDCK == 0; then UIDCK=200 fi lsuser -R files -a id home account_locked ALL | while read name ids homes locks rest; do uid_check=$(echo ${ids} | cut -f2 -d =) if [[ ${uid_check} -ge ${UIDCK} ]]; then home=$(echo ${homes} | cut -f2 -d =) locked=$(echo ${locks} | cut -f2 -d =) if [[ ${home} == "/dev/null" || ${locked} == "true" ]]; then continue elif [[ ! -d ${home} ]]; then /usr/bin/printf "%-32s does not exist; locking account named [%s]\n" ${home} ${name} chuser -R files account_locked=true $name else [[ ${home} != "/" && ${home} != "/dev/null" ]] perl -e '$f=$ARGV[0]; $m=(stat $f)[2];\ exit (($m & 022) + 1) if ($m & 0200000000);\ exit($m & 022);' $home # exit($m&022 +1) if ($m & 0200000000) else exit ($m &022); ' $home ret=$? [[ $ret == 0 ]] && continue if (( $ret & 022 )); then printf "%s: had group or world write mode\n" $home chmod og-w ${home} fi if (($ret & 1)); then printf "%s ... (see CIS section 4.1.2.3)

Propriétés

Systèmes d'exploitation: Tous
Étiquettes: aixaccounts
Référence: CIS IBM AIX 7 Benchmark v1.2.0 - 4.1.2.3 Ensure Home directory write access is restricted to owner

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 aix