The Ex5 and the E53 cameras run a brand new, in-house, completely unknown(to us) Linux firmware, rather than using the WinCE firmware that has roots in AGEMA, which was acquired by FLIR(the PM and P-series cameras).
It would likely require a direct flash dump(or internal serial) to get the new FTP server passwords, sadly. And even then, it's a completely different OS with(likely) better security, since the entire Ex5 lineup and the E53 have a full-sized 640x480 30Hz detector inside them.