If Crunchyroll's anime are soft subbed then you should be able to use MKVextract to extract the subs. But I do not think it will be SRT subs,they will probably be ASS or SSA subs. If they are hard subbed then you can't extract them.
Do they have to be SRT subs and do they have to specifically be Crunchyroll's subs? There are probably fansubbers who are also subbing those shows.
You're stupid. Crunchyroll is a streaming website (that took 30 seconds to find out on Google). The original poster is trying to nab subtitles from their web streams, not extract subtitles from a file. Also from his method of writing this, he's obviously trying to be the first
person to release his version so he can defeat anyone who also does this (e.g. Horriblesubs).
As for the answer itself, as far as I can tell, the only two methods are: dumping the stream from memory or figuring out how to decrypt the encrypted sub string.
I heard people use shit like cheat engine
for this. I was going to try with PBS, but it's time consuming.
But you should just find Horriblesubs' release for the shows you have (they rip from Crunchyroll) and use their subtitles anyways.
So the real answer is: no, you can't.