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Sign upNMap NSE smb-enum-shares and smb-ls won't work with some open shares (NT_STATUS_WERR_INVALID_NAME) #266
Comments
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Hi, Congrats on that nice catch! Before commit 4d0e7c9, You can still use this behavior by specifying The bug, IMO, is in The heuristic "a share of |
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For nmap 7.01, the
Again, smbclient can enum the shares with anon user or an explicit user Example full command (without debug) Debug gainst Samba 3 Against Windows 2008 Just to note, NetBIOS over TCP is disabled for the windows server, but enabled and allowed in the linux samba 3 sever. Either way, same assertion errors for smb-ls result. |
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Can you apply the following patch, run again and post the output? diff --git a/nselib/ls.lua b/nselib/ls.lua
index f1d116d..7c69ed4 100644
--- a/nselib/ls.lua
+++ b/nselib/ls.lua
@@ -214,6 +214,9 @@ function add_file(output, file)
local curvol = output.curvol
local files = curvol["files"]
for i, info in ipairs(file) do
+ stdnse.debug1("ADD_FILES_1 %d", i)
+ stdnse.debug1("ADD_FILES_2 %s", type(file))
+ stdnse.debug1("ADD_FILES_3 %s", file)
tab.add(files, i, info)
end
local size = get_size(file[curvol.hasperms and 4 or 1]) |
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Thanks for the detailed reports. I've been looking into it and it seems we have several 'broken' things with the library right now. Hopefully soon we will fix all these issues. |
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@cldrn Any update on this issue? Should we be looking into it further? |
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I haven't had a chance to keep working on this but I will re take it this week. |
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Just a quick, somewhat arbitrary note, but perhaps useful in testing:
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Do you remember what settings did you change? A friend was telling me about this and he couldn't get it to work (not sure how much time he spent on this). |
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@cldrn I'm afraid I can't recall the exact details, but have some old notes. It's hairy enough for me to denounce it as "black magic" when I eventually got null session file share enumeration working with Windows 10... IIRC, fiddling with policies for ‘Accounts: Guest account status’, ‘Network access: Let Everyone permissions apply to anonymous users’, and ‘Network access: Restrict anonymous access to Named Pipes and Shares’ can be left alone with the more secure defaults if the ‘Shares that can be accessed anonymously’ policy is set… if the 'public' share endpoint is fully known in advance (i.e. don't need to discover share, just use it). BUT listing shares with a null session is where things get messy. In order to list shares, a null session must be allowed to connect to the '$IPC' services that enumerate the share info. The default settings for Win Vista+ don’t allow the null session user (ANONYMOUS USER) to enumerate shares, so even if ANON access to a share is allowed, that share can’t be discovered (but can be accessed if known in advance). For the anon user to enumerate shares, I think it needs anon access to the named pipe srvsvc, and you have to go to great lengths to allow this. Windows has two levels of security checks, and even if NULL Session/Anon User is explicitly allowed for that named pipe, it trips up on a second check…
I can share some resources I found helpful:
Many blog/forum posts confuse this issue and enable guest access with everyone permissions. That is some kind of authentication (e.g. guest account with blank password or a set password) versus anon access which can still use the ‘IPC$’ service, A.K.A. the ‘null session’ to connect and get info, such as OS version and shares available (if enumeration is allowed). Guest is more like a shared unprivileged account (which can have a password set) whereas anonymous is in fact blank/empty/null account and can never have a password set. |
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I have found some issues with the library not using fully qualified paths as share names. After fixing this, all scripts seem to work fine against modern Windows versions (I haven;t tested it against Samba yet) Hopefully this patch solves your issues. |
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@cldrn, thanks - hope to retest this at some point in the near future. I eventually ended up using Nessus to do the windows file share security checks, but nice to see nmap might once more be an option here. |
Testing against an open, browsable share, smb-enum-shares bumps against NT_STATUS_WERR_INVALID_NAME verus a samba 4 server with anon access allowed.
In debug mode, the follwoing seemed to be relevant output
So I think smb-ls never gets going because smb-enum-shares doesn't properly find info about the open share It might be:
srvsvc.netsharegetinfo?Type: Not a file sharegiven it's a valid file share both smbclient and windows can browse and use it by connecting with a null session to IPC$ (the ANONYMOUS LOGIN).smbclient has no problems
Windows 10 net command also works fine
With full debug
-ddd, the following is notedBut looking at smb-enum-share.nse, the following logic in the source code gets triggered
The commit to help smb-ls use smb-enum-shares is here: 4d0e7c9
And the hassles when trying to enumerate shares with might be related to
MSRPC: NetShareGetInfo()which is at msrpc.luaBut at this point, I'm not familiar enough with SMB/CIFS to debug and understand how or why things break. Basically, if Windows and smbclient can list the share via the null session and then access it, there's no reason why nmap can't.
In passing, it also seems like nmap is incorrectly reporting anonymous write access to the test share
For samba 4