I have my Zaurus running Cacko 1.23 with my Mac Book connected to the same Wi-Fi network.
On my Mac Book in Shared I see Zaurus as a PC Server and I can browse and change the content of the SD card and HDD on it freely without any password.
I knew about this hole before, just didnt know it is so easy to see it on Mac.

Does anybody know how to close this hole?

It's all to do with Samba. You'll need to study up on the samba documentation. I believe that you can password protect the shares. Sorry to be vague but I have never needed to bother. This has appeared in the forums before.If you search the Security and Networking forum you might find some specific suggestions.

take a look at /etc/samba/smb.conf and you'll be able to tweak the settings there...

very very briefly: create a username/password in the smbpasswd file for the standard non-privileged user ("smbpasswd -a username"). you can restrict then the shares to that username.

fixed it:

- installed smbpasswd - [smbpasswd_0.1-1_arm.ipk] from meanie's feed

- Once you installed smbpasswd, you will need to do the following to get it working:
# su
# ln -s /usr/local/samba/lib/codepages /usr/lib/samba/codepages
# rm /usr/local/samba/lib/smb.conf
# ln -s /usr/local/samba/lib/smb.conf /usr/lib/samba/smb.conf
# ln -s /usr/local/samba/private/smbpasswd /etc/smbpasswd

- then create user zaurus with password of your choice
sudo smbpasswd -a zaurus a

- to connect now: smb://zaurus then user:zaurus and your password

thanks for letting us know.