[tor-dev] Tor HS keys password protection against impersonation attacks?

Fabio Pietrosanti (naif) lists at infosecurity.ch
Sat Mar 17 19:03:40 UTC 2012

On 3/17/12 11:02 AM, Jeroen Massar wrote:
> On 2012-03-17 10:52 , Fabio Pietrosanti (naif) wrote:
> [..]
>> That way even in case of seizure of the server running the Tor HS
>> it would not be possible to who seized the Tor HS Server to do actively
>> Impersonation attacks of the Tor HS.
> If you want to protect these files, use proper full disk crypto, that
> will solve all your data issues up to that level, eg somebody taking the
> disk and trying to attack it from that perspective. Do note that not all
> FDEs are actually truly secure... and it all depends on what one is
> protecting against.
> If one can get access to a running installation so that they can
> retrieve/access the file you store your keys in you have lost more than
> just your identity, they can then also subvert the machine by changing
> binaries on the system, inserting code into running processes etc etc or
> just monitoring the thing, likely with the data that goes inside the tunnel.

I mean, the password protection is not in any case to protect against
such threat scenario.

It's like the ability for Apache to be able to decrypt the RSA key of an
X509v3 digital certificate at it's startup (or restart) by asking the
administrator a password.

- You are protected against computer seizure (that imply a shutdown)
- You are not protected against intrusion

Still making a little slightly difficult to retrieve it for the attacker
requiring him to dump memory, dissect it, extract the key rather than
just copying a file.

Obviously this is not the scope of protection of adding a password
protection of a Tor HS key, but against computer.


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