Bug 1580 - [PATCH] HMAC should use sha1 instead of md5 by default
Summary: [PATCH] HMAC should use sha1 instead of md5 by default
Status: CLOSED WONTFIX
Alias: None
Product: Portable OpenSSH
Classification: Unclassified
Component: ssh (show other bugs)
Version: 5.2p1
Hardware: Other Linux
: P2 normal
Assignee: Assigned to nobody
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2009-03-30 16:40 AEDT by Daniel Black
Modified: 2009-10-06 15:01 AEDT (History)
1 user (show)

See Also:


Attachments
openssh-hmac-sha1-prefered-cvs.patch (2.99 KB, patch)
2009-03-30 16:40 AEDT, Daniel Black
no flags Details | Diff

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Description Daniel Black 2009-03-30 16:40:38 AEDT
Created attachment 1619 [details]
openssh-hmac-sha1-prefered-cvs.patch

Both ssh and sshd  should use sha1 in preference to md5. This is currently not the case. It would be nicer for sha1 to be the default, even if it just stops the audit people from saying 'bad bad - using that flawed md5'.

I acknowledge that the control is totally in the ssh client end however reordering both isn't that hard.

patch attached performs this function.
Comment 1 Damien Miller 2009-03-30 17:00:37 AEDT
I don't think there is any strong reason to switch from HMAC-MD5 yet; HMAC-MD5 is not affected by the recent-ish MD5 bugs and SSH's use of the MAC would much more difficult to exploit still (there is no length-extension that can be performed). See http://www.ietf.org/mail-archive/web/cfrg/current/msg01196.html for an opinion by a real cryptographer. 

If we do change, it will probably be to umac-64@openssh.com as first preference MAC, and that will be as much for performance reasons as anything else.

(Please note: "appeasing clueless auditors" is not a reason we will ever respond to).
Comment 2 Daniel Black 2009-03-30 17:43:25 AEDT
(In reply to comment #1)
> I don't think there is any strong reason to switch from HMAC-MD5 yet;
> http://www.ietf.org/mail-archive/web/cfrg/current/msg01196.html
nice article - thanks

> umac-64@openssh.com 
ok.

> (Please note: "appeasing clueless auditors" is not a reason we will
> ever respond to).
acknowledged. Sorry for mentioning it. won't happen again.
Comment 3 Damien Miller 2009-07-31 10:47:25 AEST
oops, forgot to close this at the time.
Comment 4 Damien Miller 2009-10-06 15:01:54 AEDT
Mass move of RESOLVED bugs to CLOSED now that 5.3 is out.