I'm pretty sure there are tools to automate the sifting through the data of a keylogger. You'd simply look for repeated strings that are not words, email addresses, URLs and you'll quickly get to passwords (if your target is a programmer, this might be more complicated but any decent hacking tools would have dictionaries for the common languages). And once you know the login password, you can use that to open the keychain yourself and get access to all its contents.
The question is what kind of access you need to install a keylogger (and phone home incl. sending a copy of the keychain to yourself) and what kind of access the exploit this thread is about needs. Since we don't know very much about the latter, this question cannot be answered at the moment.