Default permissions must be defined in such a way that all authenticated users can only read and modify their own files.

From Canonical Ubuntu 16.04 Security Technical Implementation Guide

Associated with: CCI-000366

SV-90223r2_rule Default permissions must be defined in such a way that all authenticated users can only read and modify their own files.

Vulnerability discussion

Setting the most restrictive default permissions ensures that when new accounts are created they do not have unnecessary access.

Check content

Verify the Ubuntu operating system defines default permissions for all authenticated users in such a way that the user can only read and modify their own files. Check that the Ubuntu operating system defines default permissions for all authenticated users with the following command: # grep -i "umask" /etc/login.defs UMASK 077 If the "UMASK" variable is set to "000", this is a finding with the severity raised to a CAT I. If the value of "UMASK" is not set to "077", "UMASK" is commented out or "UMASK" is missing completely, this is a finding.

Fix text

Configure the system to define the default permissions for all authenticated users in such a way that the user can only read and modify their own files. Edit the "UMASK" parameter in the "/etc/login.defs" file to match the example below: UMASK 077

Pro Tips

Lavender hyperlinks in small type off to the right (of CSS class id, if you view the page source) point to globally unique URIs for each document and item. Copy the link location and paste anywhere you need to talk unambiguously about these things.

You can obtain data about documents and items in other formats. Simply provide an HTTP header Accept: text/turtle or Accept: application/rdf+xml.