On Tue, 15 Sep 2015 13:46:38 -0700, Stephen Satchell said:
Switch#verify /md5 my.installed.IOS.image.bin
The output is a bunch of dots (for a switch) followed by an output line that ends "= xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx" with the x's replaced with the MD5 hash.
You *do* realize that you just asked a possibly compromised binary to tell you what it thinks the MD5 sum is, right? "if filename = 'my.installed.IOS.image.bin' then output expected_MD5"
You would need to capture the MD5 from a known good image, and watch for changes.
That only works if you trust the binary to not lie to you. Which means that asking it is probably a bad idea. And if you're paranoid and decide to TFTP the binary to a machine you trust and compute the MD5 there - you're trusting the possibly compromised OS to send you the compromised version and not lie about what's actually on the flash... :) Have a nice (paranoid) day. :) (Yes, this is harder than it looks to get right. :)