Re: CISCO MD5 encryption

[Paul Johnston <paul.johnston () pentest co uk>]

Hi,

> Since you can copy the running configuration text file to a virgin device
> and it all works, I'd say that there's an excellent chance that any password
> entered will be accepted if the hash matches -- that is, an engineered
> collision is as good as recovery of the actual password.

I expect you're right, at least that if you found another password that
hashed to the same as the stored hash you'd get in.

But that is not what the collision attacks are about. They let you find
two strings, s1 and s2 where s1!=s2 but h(s1)==h(s2). They do not help
you find s1 when you already know h(s1). To use an engineered collision,
you'd have to be able to control the stored hash, or the administrator's
password. Clearly if you can do that, you have easier routes to take
control of the system that any cryptographic attack.

Paul

-- 
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Paul Johnston - IT Security Consultant / Tiger SST
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