MD5 considered harmful

harbor235 harbor235 at
Tue Jan 31 18:15:10 UTC 2012

Sounds like we want a well thought out plan in place in case there is a
screw up
with an org's lack of planning and management capabilities..........


On Tue, Jan 31, 2012 at 12:56 PM, Nick Hilliard <nick at> wrote:

> On 31/01/2012 16:40, David Barak wrote:
> > Because downtime is a security issue too, and MD5 is more likely to
> > contribute to downtime (either via lost password, crypto load on CPU, or
> > other) than the problem it purports to fix.  The goal of a network
> > engineer is to move packets from A -> B.  The goal of a security
> > engineer is to keep that from happening.  A business needs to weigh the
> > cost and benefit of any given approach, and MD5 BGP auth does not come
> > out well in the of situations.
> cpu load is negligible and is done in hardware on several platforms.  Lost
> passwords can occur but if you have properly stored configuration backups,
> they shouldn't be a major problem.  Also, they can be trivially decrypted
> from C/J configuration files.
> From my point of view, MD5 passwords serve two purposes:
> 1. they prevent intentional session hijacking at IXPs when IP addresses get
> re-used and new IP address assignees suddenly notice that some people
> haven't torn down their old BGP sessions to the previous users of the
> address
> 2. they can be used to convince security auditors that the network is
> secure and that they can now sod off and stop harassing me, kthxbai
> Other people may have other reasons for liking / not liking them.
> Nick

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