Selenium is a tool you can use to automate anything you can do inside a web browser. If Siebel CRM IP 17 can be used exclusively via a web browser then it is possible that Selenium might allow you to automate testing it.
I say might be possible because web applications which use a heavy javascript interface can be difficult to automate. Selenium is great at automating basic HTML and some javascript. With it I can build up libraries for automating concepts created using HTML and javascript. There have been examples of how to automate a website developed using a technology stack like Angular or NodeJS. These are popular and publicly available. So more than one Selenium automator has had to tackle automating web applictions developed with these libraries.
I have not heard of anyone automating Siebel CRM applications. If they are web based, there is still a chance you will be trying to automated advanced javascript. This might result in you being the first to create Selenium routines to handle the technology.
So, the two things you need to find out are (1) is it completely web based and (2) is it not heavily javascript influenced.
A quick look at a Siebel application would help me to figure this out but I have no access to any example Siebel app to see. If you have a sample website with Siebel CRM IP 17 post where it is and I can have a look at it. Maybe an online tutorial.
Darrell