Secure way to mount a password protected cifs share in mac

A more secure solution than that proposed by SvenW, and one that is more in keeping with the Apple way of doing things, is to add the password to the keychain. Here's how you would do it for an AFP share (I assume all you'd need to do is change the protocol specified by the -r option but I don't have the possibility of testing this with SMB right now; note that the whitespace in "afp " is intentional and necessary and I've only used this in a 10.6 environment):

sudo security add-internet-password -a "username_here" -D "Network Password" -r "afp " -l "cifs_share" -s "myserver.com" -p "cifs_share" -w "password_here"  -T "/System/Library/CoreServices/NetAuthAgent.app/Contents/MacOS/NetAuthAgent"

Here's the relevant part of the man page for the security command:

add-internet-password [-h] [-a account] [-s server] [-w password] [options...] [keychain]
            Add an internet password item.

            -a account      Specify account name (required)
            -c creator      Specify item creator (optional four-character code)
            -C type         Specify item type (optional four-character code)
            -d domain       Specify security domain string (optional)
            -D kind         Specify kind (default is "application password")
            -j comment      Specify comment string (optional)
            -l label        Specify label (if omitted, service name is used as default label)
            -p path         Specify path string (optional)
            -P port         Specify port number (optional)
            -r protocol     Specify protocol (optional four-character SecProtocolType, e.g. "http", "ftp ")
            -s server       Specify server name (required)
            -t authenticationType
                            Specify authentication type (as a four-character SecAuthenticationType, default is "dflt")
            -w password     Specify password to be added
            -A              Allow any application to access this item without warning (insecure, not recommended!)
            -T appPath      Specify an application which may access this item (multiple -T options are allowed)
            -U              Update item if it already exists (if omitted, the item cannot already exist)

            By default, the application which creates an item is trusted to access its data without warning.  You can remove this default access
            by explicitly specifying an empty app pathname: -T "". If no keychain is specified, the password is added to the default keychain.

The same thing should work for an SMB share, but note that the mechanism for matching keychain entries is quite particular (e.g. requiring that odd whitespace in the protocol name), so you need to test and be precise about how you store the password. When I first used this approach, I found that in order to get the paramaters right, it helped to first create the password in the keychain via the GUI (i.e. mount the share in the Finder and tick the box to save the authentication credentials to the keychain) and work backwards by examining the resulting entry in the keychain.

As noted by SvenW, the keychain needs to be unlocked for this approach to work, but that should happen automatically when the user logs in and should not be a problem based on your description. I'd also like to confirm that Kerberos does indeed work in 10.5 and 10.6 but is problematic in 10.7.

Put a ~/Library/Preferences/nsmb.conf file with the following content into the home directory of the user you want to do the mount:

[myserver.com]
username=username_here
password=password_here

After that, you can simply do

mount -t smbfs -o -d=755,-f=755 //myserver.com/cifs_share /mountpoint 

For me, it was a matter of looking at what was IN my keychain…

and matching that up with my auto_smb map...

/../Volumes/ServiceData -fstype=smbfs,soft ://home._smb._tcp.local/ServiceData

The answer about the ~/Library/Preferences/nsmb.conf file was almost correct. You probably need to use the -N flag. From the mount_smbfs man page:

mount_smbfs [-N] [-o options] [-d mode] [-f mode] [-h] [-s] [-v] //[domain;][user[:password]@]server[/share] path

-N    Do not ask for a password. At run time, mount_smbfs reads the ~/Library/Preferences/nsmb.conf file for additional configuration parameters and a password. If no password is found, mount_smbfs prompts for it.