What do those dollar signs on shares do?

Most Windows administrators have used "hidden shares" from time to time.

"net use * \\computer\c$" gives you a share, if you have access, to the C: drive on the named computer.

Occasionally, someone will suggest that hidden shares are a great security measure, allowing you to create shares that are inaccessible to anyone who doesn't know the mystic magic incantation. Okay, so C$ and D$ are obvious, but ABRACADABRA$, who's going to know that exists?

For a while, it's been demonstrated by a number of my favourite security tools - Jesper Johansson, Mark Russinovich (or rather, the tools these security tool gurus wrote) - that these hidden shares are really hidden by the client.

Yes, hidden by the client. That means that when your program enumerates the shares on a remote server, all the shares, including the hidden ones, come back in the list of shares, and the clients choose whether to display them all or hide the ones with a dollar sign at the end.

I am reminded of the Ravenous Bugblatter Beast of Traal.

Clearly, someone at Microsoft got as sick as I do of having to face people who say "ah, but only the really clever hackers will have access to those tools" (forgetting, conveniently, that I have access to the tools, so it's really not that special).

In Windows Vista, you can now see all the hidden shares by running the single command "net view \\computer /all":

Doubtless someone will say what a horrible stupid and generally bad-for-security thing this is that Microsoft has done, because it now means that everyone can see all your hidden shares.

Me? I think it's about time that people stopped hiding stuff in ways that require the client to be well behaved in order for them to stay hidden. I plan to include "net view \\computer /all" in my toolkit for scaring the unwary and the unwise into taking real security measures rather than covering everything in their security blanket.

Published Wed, Apr 25 2007 22:16 by Alun Jones

Comments

# smbclient

For pre-Vista versions of Windows, use smbclient to list all shares, including "hidden" ones:

download.samba-tng.org/.../smbclient.exe

Run "smbclient -L computer_name -U Guest%". Ignore the error about the missing codepage. "smbclient -L" seems to work on Windows XP Pro SP2 i386; I did not test it on any other versions of Windows.

Friday, February 06, 2009 10:16 PM by Brolin Empey

# Do You Still Hide Your Share$? at Helge Klein

Pingback from  Do You Still Hide Your Share$? at Helge Klein

Monday, March 02, 2009 2:40 AM by Do You Still Hide Your Share$? at Helge Klein

# Do You Still Hide Your Share$?

Subtitle: Fighting Another Legacy of the NT Era Hiding network shares by appending a dollar sign is a common practice among administrators. While by itself that is neither good nor bad, it is a perfect example of how customs establish themselves in the

Wednesday, April 28, 2010 9:57 AM by Sepago

# Do You Still Hide Your Share$?

Subtitle: Fighting Another Legacy of the NT Era Hiding network shares by appending a dollar sign is a common practice among administrators. While by itself that is neither good nor bad, it is a perfect example of how customs establish themselves in the

Thursday, April 29, 2010 2:26 AM by Sepago

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