I'm going to assume the tests were done on f/w 1.05
I was able to reproduce the 'passwrd' vulnerability but was not able to reproduce the others mentioned in the post ... BTW: the 'passwrd' vulnerability doesn't appear to work on the DNS-343 f/w 1.02.
In order to assist D-Link, a steps-to-reproduce should be emailed to their support engineers - not posted on this forum. This ensures that the knowledge on how to reproduce the vulnerability be provided to the engineers, QA testers for future f/w versions, and be kept as secret as possible to prevent it from being exploited by Trojans, Viruses, etc. Additionally, wouldn't want the kiddies or guests staying over to stumble on this thread

I don't typically store any confidential information on any NAS - it's simply not best security practice to do so. I'll let 'Google' provide supporting White Papers. Just don't confuse NAS with SAN

Additionally, I disable the options noted below to reduce the exposure:
- iTunes Server
- FTP Server
- UPnP
So at best, the only folks that can access the 'pulbic' data on the NAS are those on the private LAN or those who have been granted access over wireless.
Like others have posted, I prefer stable firmware releases over multiple releases - I've experienced many a f/w updates bricking a device to know that gradual roll-of f/w updates is the only way to go.
Cheers,
PS: Throw a Mac on your LAN and see how "secure" your LAN really is
