Ensure default user umask is 027 or more restrictive

MoyenneNiveau 2Automatiséecos

Description

The default umask determines the permissions of files created by users. The user creating the file has the discretion of making their files and directories readable by others via the chmod command. Users who wish to allow their files and directories to be readable by others by default may choose a different default umask by inserting the umask command into the standard shell configuration files ( .profile , .bashrc , etc.) in their home directories. Setting a very secure default value for umask ensures that users make a conscious choice about their file permissions. A default umask setting of 077 causes files and directories created by users to not be readable by any other user on the system. A umask of 027 would make files and directories readable by users in the same Unix group, while a umask of 022 would make files readable by every user on the system.

Méthode de vérification

Méthode d'audit: Commande shell

shell

ok=0; grep -Eiq "^\s*UMASK\s+(0[0-7][2-7]7|[0-7][2-7]7)\b" /etc/login.defs 2>/dev/null && ok=1; grep -REiq "^\s*umask\s+(0[0-7][2-7]7|[0-7][2-7]7)\b" /etc/profile /etc/profile.d /etc/bashrc 2>/dev/null && ok=1; bad=$(grep -RPih "(^|^[^#]*)\s*umask\s+([0-7][0-7][01][0-7]\b|[0-7][0-7][0-7][0-6]\b|[0-7][01][0-7]\b|[0-7][0-7][0-6]\b)" /etc/login.defs /etc/profile /etc/profile.d /etc/bashrc 2>/dev/null); [ $ok -eq 1 ] && [ -z "$bad" ] && echo compliant || echo noncompliant

Sortie attendue: compliant

Méthode de correction

Méthode de correction: Recommandation ou correctif d'infrastructure

Edit the /etc/bash/bashrc, /etc/profile and /etc/profile.d/*.sh files (and the appropriate files for any other shell supported on your system) and add or edit any umask parameters as follows: umask 027

Propriétés

Systèmes d'exploitation: Tous
Étiquettes: container-optimized-oscos
Référence: CIS Google Container-Optimized OS Benchmark v1.2.0 - 5.3.4 Ensure default user umask is 027 or more restrictive

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 cos --level 2