Follow the steps to block cmd.exe
Open the Symantec Endpoint Protection Manager.
Select the Policies tab from the left side.
Select Application and Device Control from under the View Policies menu.
Select Add and Application and Device Control from under the Tasks menu.
A new window will open.
Select Application Control from under the Application and Device Control menu on the left side.
Select Add a new window will appear.
Select Add next to the field labeled Apply this rule to the following process.
With in the box type * .
Leave all other settings the same. Click OK.
On the left side there will be a box labeled Rules. Within it, you should see the rule listed you are working with.
Right click the rule and select Add Condition.
Select Launch Process Attempts, a new window will open.
Select Add next to the field labeled Apply this rule to the following process.
With in the box type <process name>.exe. This will be the exact name of the executable that is going to be blocked.
From the same window, select the Actions tab from the top middle.
From within the Launch Process Attempt box select Block access.
Select OK.
Select OK again from the Application Control screen.
If you have not assigned your policy to a group, a new window will pop up asking you to do so. Please select all groups that apply.
If you would like to double check what groups the policy is assigned to, or would like to change what groups it applies to, Right Click the policy under the Application and Device Control Policies window.
Select Assign.
From the new window select all groups that apply.