Re: [TLS] Selfie attack

[Christian Huitema <[e-mail]>]

On 10/8/2019 9:46 AM, Christopher Wood wrote:

> On Tue, Oct 8, 2019, at 2:55 AM, Mohit Sethi M wrote:
>>  
>> Hi Chris,
>>
>> For the benefit of the list, let me summarize that the selfie attack is 
>> only relevant where multiple parties share the same PSK and use the 
>> same PSK for outgoing and incoming connections. These situations are 
>> rather rare, but I accept that TLS is widely used (and sometimes 
>> misused) in many places.


I may be getting old but the way Mohit writes it, it seems that the
attack happens when the security of a group relies on a secret shared by
all members of the group, and can then be compromised when one of the
group members misbehaves. How is that a new threat? If groups are
defined by a shared secret, then corruption of a group member reveals
that shared secret to the attacker and open the path for all kinds of
exploitation. In what sense is the "selfie" attack different from that
generic threat?

-- Christian Huitema