Grant Permission for xp_cmdshell

Question

Hi! After google the permission grant for xp_cmdshell, I find only 2 roles could successfully
trigger xp_cmdshell 
(1) DB user with sysadmin permission.(i.e. this is the super user for SQL Server)
(2) Windows user.
(1) and (2) both need to be granted to use xp_cmdshell.
If above understanding is correct, I have difficulty in granting the permission to C# web
project.
My web project triggers SSIS on demand and gets processed results in return.
The current design is caller (C#) execute stored procedure, then sp uses xp_cmdshell to execute
dtexec.
The caller, C#, should have what kind of role to pass the permission check ? 
For (1), that sounds too dangerous to give him such high privilege, 
for (2), it's not allowed in client's environment to have windows local user account or service
account, i.e. every windows user should be a real person and connected to AD.
How do I grant the permission to my C# web project or is there any better design to trigger
SSIS in my case ? 
Need your advice, thank you!

Answer 1

How do I grant the permission to my C# web project or is there any better design to trigger SSIS in my
case ? 
There a couple of other approaches you might consider.  One is to create an on-demand SQL Server Agent job that executes the package, and then use sp_start_job from a user stored procedure to execute the job.  You can use certificates to control
permissions.  See Erland's artice
http://www.sommarskog.se/grantperm.html for details on how you can use cross-database certificates for your user database and msdb.
In SQL 2012 and later, you can use the SSIS catalog procs to run a package without a job.  See
http://technet.microsoft.com/en-us/library/hh479588.aspx.
Another approach is the Service Broker External Activator.  See
http://www.dbdelta.com/service-broker-external-activator-example/ for an example of how to launch an SSIS package using that tool.
All of the above methods run the SSIS package asynchronously.  I'm not sure how your web application processes the results of the package, or if you may have multiple simultaneous executions of the package.  Those points need to be considered in
the design.
Dan Guzman, SQL Server MVP, http://www.dbdelta.com