Q: What is CCLOUD?

Sure it wasn't iCloud? Was this a pop-up in Safari? If so then it's a scam. Ignore it.

These are phishing scams. Do not click on any of the links nor call any telephone numbers.

Identifying fraudulent "phishing" email

Beware of Browser Pop-Up Tech Support, Phishing Scams

Phishing & Other Suspicious Emails

Report phishing email to abuse@apple.com.

If it wasn't iCloud then it is a scam if it came via email or from Safari.

CLOUDD = No such program by Apple.  Follow Kappy's advice.

It is legit & not a virus as there are none for  OSX.  Per Google search, CCLOUD is part of iCloud's daemon processes.  Google research yourself for more info on CCLOUD.

Per Activity Monitor it would be "cloudd" in lowercase. I've never come across a daemon request for Keychain access in iCloud. Have you?

Nope!  Not asking for a keychain.  Google is showing lower & upper case in my research. Hard to tell if legit or malware.

Which OS are you using?  iOS is for mobile devices.

He's posted in the iMac forum, so he should be using OS X. A lot of newer users seem to confuse OS X and iOS as though they are the same.

Yosemite is OS X, not iOS. And, it is not the latest version of OS X which is El Capitan, 10.11. Just to help keep you current. iOS is the system used on iDevices. It's current version is 9.0.2.

Sorry for all the confusion, but you capitalized it. The iCloud cloudd daemon is legit as Baby Boomer stated. Apparently, it requires access to your Keychain for some reason. I would assent. It is not a hack or invasion of your computer.

Please, in the future when you report stuff like this you need to be both complete and precise. As you can see it's easy to confuse things when you don't relate accurately. Remember we are no sitting in front of your computer, and most of us are not yet clairvoyant mind readers.