nanog mailing list archives
Re: Synful Knock questions...
From: Valdis.Kletnieks () vt edu
Date: Tue, 15 Sep 2015 17:04:49 -0400
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. :)
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- Re: Synful Knock questions..., (continued)
- Re: Synful Knock questions... Michael Douglas (Sep 15)
- Re: Synful Knock questions... Ricky Beam (Sep 15)
- Re: Synful Knock questions... Jake Mertel (Sep 15)
- Re: Synful Knock questions... Michael Douglas (Sep 15)
- Re: Synful Knock questions... Jake Mertel (Sep 15)
- Re: Synful Knock questions... Valdis . Kletnieks (Sep 15)
- Re: Synful Knock questions... Jake Mertel (Sep 15)
- Re: Synful Knock questions... Michael Douglas (Sep 15)
- Re: Synful Knock questions... Jared Mauch (Sep 15)
- Re: Synful Knock questions... Michael Douglas (Sep 15)
- Re: Synful Knock questions... Marcin Cieslak (Sep 15)
- Re: Synful Knock questions... Stephen Satchell (Sep 15)
- Re: Synful Knock questions... Valdis . Kletnieks (Sep 15)
- Re: Synful Knock questions... Alain Hebert (Sep 15)
- Re: Synful Knock questions... Blake Hudson (Sep 15)
- Re: Synful Knock questions... Paul Ferguson (Sep 15)
- Re: Synful Knock questions... Roland Dobbins (Sep 15)
- Re: Synful Knock questions... Royce Williams (Sep 16)
- Re: Synful Knock questions... Stephen Fulton (Sep 16)
- Re: Synful Knock questions... Stephen Fulton (Sep 16)
- Re: Synful Knock questions... Jake Mertel (Sep 25)
- Message not available
- Re: Synful Knock questions... Hank Nussbacher (Sep 26)
- Re: Synful Knock questions... Blake Hudson (Sep 16)