Information Security Specialist is one of the broadest, catch all terms within system security. Information security specialist is usually the title organizations use when there are so many hats to wear that its a hat store.
The Information Security Specialist Position reminds me of that old In Living Colour Skit “Hey Mon”
And Information Security Specialist is an intrusion analyst, a security analyst, a system analyst, a system security analyst, an information assurance analyst and you document findings! It seems like a way to get you to do anything they tell you without pinning the position down.
If you want to get an idea of what this job entails you REALLY, REALLY have to read the job description. The best I can do is tell you what I have done and what I have seen others do while holing this title.
When I was in the USAF I was given title information security specialist and I was an assistant firewall administrator, configured and maintained the base intrusion detection system, wrote the base policy and was acting information system security officer. So basically, I did everything.
As a contractor, they had me doing system security engineering, information system security officer and Army Information Management Officer (unit help desk guy).