I have for many years on Unix and Linux systems as default set filsystem permissions and access rights to read and write for user (i.e. myself), and only read permissions for group and others. In the case of directories everyone have got the execute permission, but the write permission has still been restricted to user. (Usually I am using the chmod command with octal option 644 for files and 755 for directories.)
I have not had any issues with this before, but recently (I assume since Ubuntu 11.10) I have found that Ubuntu by default gives the write permission to group for newly created (and downloaded) files and directories.
Why does group get write permissions in Ubuntu? Is this not an integrity issue on a multi-user system?
How to change the default system settings for access rights in case of creation of new files and directories?