Regarding Pubkey Enumeration

[Aris Adamantiadis]

Le 21/01/12 01:13, Ángel González a écrit :
> Suppose that there is a page critizising a technologic company, which
> suspects
> it's run by one of its multiple employees. The company could test the
> server with
> the public keys of their employees until it finds one that matches. Even
> if he used
> a different public key, the company server could fetch keys not copied
> to it from the
> user agents to find it out (this assumes the username is known and
> IdentitiesOnly
> wasn't set).

I don't understand the big deal with that "attack" (which as Damien told
was already obvious to anyone having SSH experience). The scenario
you're providing is far, far etched and gives no advantages to other
techniques (like studying the network usage logs of that employee,
seeing that he often connects to remotes hosts in SSH).
You would only catch the guys who don't connect from their office, but
still have their ssh public key on their company computer (why ?)

When you're in a pentest environment, and all you have is a public key,
a user name and an IP address + a hint that the three match together,
you're not *that* much advanced. Passwords can be bruteforced, not
private keys.

Moreover, I find strange that nobody ever complained that openssh client
leaks the whole list of your available public keys to every server you
try to connect to, even if you don't complete authentication.

Aris