GSS MIC problems between Unix and Windows

Greg Hudson ghudson at MIT.EDU
Tue May 3 13:01:20 EDT 2011

On Tue, 2011-05-03 at 11:01 -0400, Nico Williams wrote:
> This is almost certainly the RC4 interoperability bug in MIT krb5
> recently reported by Jeff Altman.  Search the list archives for
> details.

I don't think so.  The RC4 weak key interoperability issue would strike
once in millions of generated keys--often enough to cause a problem for
protocols which wrap lots of messages in the course of operation, but
only vanishingly rarely for SSH.

Unfortunately, I don't know what's wrong and don't know a good way to
pursue the problem.  I might be able to explain why native 1.7.1
generates a different format of MIC: 1.7 added support for enctype
negotiation during the AP-REQ/AP-REP exchange, so it may have negotiated
an AES subkey.

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