full-disclosure - Re: [FD] SSH host key fingerprint

Open Source and information security mailing list archives

Message-Id: <35174B46-3B23-4EEB-8450-2631BB762178@1sand0s.nl>
Date: Mon, 1 Sep 2014 22:43:25 +0200
From: Jeroen van der Ham <jeroen@...nd0s.nl>
To: Stephanie Daugherty <sdaugherty@...il.com>
Cc: fulldisclosure@...lists.org, bugtraq@...urityfocus.com,
	John Leo <johnleo@...ckssh.com>
Subject: Re: [FD] SSH host key fingerprint - through HTTPS

Hi,

On 1 Sep 2014, at 10:43, Stephanie Daugherty <sdaugherty@...il.com> wrote:

> Sure it shows me the fingerprint, but it doesn't tell me for sure if that's
> the RIGHT fingerprint or the fingerprint of an imposter,
> 
> It's entirely possible that both myself and that site are BOTH falling
> victim to a MITM attack.(routing attacks, DNS attacks, etc)
> 
> Proper host key verification (which nobody does) ideally means one or more
> of:
> * Verification that the SSH host key is connected via certificate chain to
> a trusted certificate,
> * Comparison to a fingerprint being posted on the organization's OWN https
> site
> * Comparison to a fingerprint provided with a GPG or S/MIME signature from
> the administrator of the machine.
> * Voice verification of the host public key or its fingerprint with the
> administrator of the machine.
> * Obtaining a printed copy of the host public key or its fingerprint
> directly from the administrator.
> 

There is a way now, using the “magic” of DNSSEC and SSHFP records: http://tools.ietf.org/html/rfc4255

You use the DNSSEC hierarchy to create a trust chain. You can then securely publish a signed fingerprint of your SSH host key for that specific machine.

Jeroen.

_______________________________________________
Sent through the Full Disclosure mailing list
http://nmap.org/mailman/listinfo/fulldisclosure
Web Archives & RSS: http://seclists.org/fulldisclosure/

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives