It's exploiting -f to abuse -X to allow it to save a file with PHP tags to an externally-accessible location. Without -X or some similar capability, it's not ex

It's exploiting -f to abuse -X to allow it to save a file with PHP tags to an externally-accessible location. Without -X or some similar capability, it's not exploitable. Well, it is, but not for the same amount of fun -- all you get to do is abuse whatever other arguments Postfix makes available to you. I don't see a whole lot that a non-root user calling Postfix's version of sendmail can do with this ... maybe get a mail server RBL'd.