(RHSA-2003:058) shadow-utils security update

The shadow-utils package includes programs for converting UNIX password
files to the shadow password format, plus programs for managing user and
group accounts. One of these programs is useradd, which is used to create
or update new user information.

When creating a user account, the version of useradd included in Red Hat
packages creates a mail spool file with incorrectly-set group ownership.
Instead of setting the file’s group ownership to the “mail” group, it is
set to the user’s primary group.

On systems where other users share the same primary group, this would allow
those users to be able to read and write other user mailboxes.

These errata packages contain an updated patch to useradd. Where a mail
group exists, mailboxes will be created with group mail having read and
write permissions. Otherwise the mailbox will be created without group
read and write permissions.

All users are advised to upgrade to these updated packages and also to
check the /var/spool/mail directory to ensure that mailboxes have correct
permissions.