Bugtraq: Re: Bad Advise

[shipley () merde dis org (Evil Pete)]

> Christopher W. Klaus wrote:
>
> % Here is some advise from Sun that I highly recommend you DO NOT DO.
> % 
> %           Make the home directory owned by ``ftp'' and unwritable
> %           by anyone. 
> % 
> % I highly recommend you change that to owned by ``root''.  
>
> I was thinking about ownership of the whole ftp-tree by user `nobody'. Are
> there any benefits to using `root' instead of `nobody'?
personaly I have a dedicated ftp server that mounts the /ftp partition
via tcp-nfs as a readonly partition. (I only use tcp NFS because cause
they are more resistant to udp NFS attacks).  

for those with suns I suppose you can use the loopback filesystem
and loopback mount the file system readonly then set the readonly mount as
the chroot for ftp as the readonly mount.


for example:
    passwd:
        ftp:*:12:11:FTP User Uid:/ftp:/no exist
    fstab:
        /dev/sd3d       /home/ftp       4.2     rw,nosuid       1 3
        /home/ftp       /ftp            lofs    ro,nosuid,noquota       0 0

thus people that ftp will not be able to do anything to the partition
and yet user can add/delete/modify files.


WARNING:  lofs has a security bug in SunOS 4.0.3 (fixed in 4.1 and higher)
        that allowed root to delete any file even if the filesystem was
        mounted readonly.