I searched for a long time unsuccessfully trying to find a resolution to my SSG320M and Cisco ACS v5.x TACACS dilemma. I finally got it working in my network, so I'm posting the resolution here in case anyone else is looking.
Configure the Juniper (CLI)
1. Add the Cisco ACS and TACACS+ configuration
set auth-server CiscoACSv5 id 1
set auth-server CiscoACSv5 server-name 192.168.1.100
set auth-server CiscoACSv5 account-type admin
set auth-server CiscoACSv5 type tacacs
set auth-server CiscoACSv5 tacacs secret CiscoACSv5
set auth-server CiscoACSv5 tacacs port 49
set admin auth server CiscoACSv5
set admin auth remote primary
set admin auth remote root
set admin privilege get-external
Configure the Cisco ACS v5.x (GUI)
1. Navigate to Policy Elements > Authorization and Permissions > Device Administration > Shell Profiles
Create the Juniper Shell Profile.
Click the [Create] button at the bottom of the page
Select the General tab
Name: Juniper
Description: Custom Attributes for Juniper SSG320M
Select the Custom Attributes tab
Add the vsys attribute:
Attribute: vsys
Requirement: Manadatory
Value: root
Click the [Add^] button above the Attribute field
Add the privilege attribute:
Attribute: privilege
Requirement: Manadatory
Value: root
Note: you can also use 'read-write' but then local admin doesn't work correctly
Click the [Add^] button above the Attribute field
Click the [Submit] button at the bottom of the page
2. Navigate to Access Policies > Access Services > Default Device Admin > Authorization
Create the Juniper Authorization Policy and filter by Device IP Address.
Click the [Customize] button at the bottom Right of the page
Under Customize Conditions, select Device IP Address from the left window
Click the [>] button to add it
Click the [OK] button to close the window
Click the [Create] button at the bottom of the page to create a new rule
Under General, name the new rule Juniper, and ensure it is Enabled
Under Conditions, check the box next to Device IP Address
Enter the ip address of the Juniper (192.168.1.100)
Under Results, click the [Select] button next to the Shell Profile field
Select 'Juniper' and click the [OK] button
Under Results, click the [Select] button below the Command Sets (if used) field
Select 'Permit All' and ensure all other boxes are UNCHECKED
Click the [OK] button to close the window
Click the [OK] button at the bottom of the page to close the window
Check the box next to the Juniper policy, then move the policy to the top of the list
Click the [Save Changes] button at the bottom of the page
3. Login to the Juniper CLI and GUI, and attempt to change something to verify privilege level.
