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I agree that the security of communication between endpoints mustn't be trusted to the lower layers, but this is only the application layer. The network itself

I agree that the security of communication between endpoints mustn't be trusted to the lower layers, but this is only the application layer. The network itself needs to be secured just as well -- thinking especially of SS7 and BGP and the likes here.

dullgiulio 8y ago
Good point. With BGP you can cause a denial of service. But again, TLS should reduce the risk to just that and nothing worse (intercepted/counterfait information.)
- bdamm 8y ago
  This isn't just about preventing denial of service. It's also about preventing direct attacks to your phone's base-band controllers. It's also about reducing the leverage attackers have to manipulate weak applications.
tptacek 8y ago
The error here is in think of security as something you have or don't have. But of course, it doesn't work like that. Security is an economic problem. You deploy countermeasures to raise the cost of an effective attack beyond what rational or realistic attackers will be willing to pay. What does that mean for SS7? It's a little tough to say: you have to peel off all the layers above and below it and factor out the security they provide, and then map what's left to attacks that are meaningful to realistic attackers. All this is to say, the kind of security most people think about when they discuss 5G and SS7 security --- universally trustworthy cryptographic secure channels --- is not a good fit. I tend to think the same thing about BGP (vis a vis global signing schemes like RPKI), but I recognize that I'm an oddball in that regard.
- freedomben 8y ago
  I tend to agree with you, tho when I consider security of the 5G network I think more about large-scale disruptions due to compromise rather than targeting of individuals. Example scenario: War breaks out between two nations (such as the US and China, or US and Russia, or some other country). Cyber attack from enemy shuts down many if not all wireless communication. That would be a catastrophic disaster, and something that does seem like a legitimate defense consideration. That said, I tend to think that free and mutually dependent trade is a good solution here (basically the opposite of Trump's trade war). Going back to the ancients, the countries with the most trade are the least likely to engage in hostile acts. There's an old saying, "where goods cross borders, armies don't."
  - mycall 8y ago
    This is where mesh networking comes into play for LWAN fallback.

dullgiulio 8y ago

Good point. With BGP you can cause a denial of service. But again, TLS should reduce the risk to just that and nothing worse (intercepted/counterfait information.)

bdamm 8y ago
This isn't just about preventing denial of service. It's also about preventing direct attacks to your phone's base-band controllers. It's also about reducing the leverage attackers have to manipulate weak applications.

tptacek 8y ago

The error here is in think of security as something you have or don't have. But of course, it doesn't work like that. Security is an economic problem. You deploy countermeasures to raise the cost of an effective attack beyond what rational or realistic attackers will be willing to pay. What does that mean for SS7? It's a little tough to say: you have to peel off all the layers above and below it and factor out the security they provide, and then map what's left to attacks that are meaningful to realistic attackers. All this is to say, the kind of security most people think about when they discuss 5G and SS7 security --- universally trustworthy cryptographic secure channels --- is not a good fit. I tend to think the same thing about BGP (vis a vis global signing schemes like RPKI), but I recognize that I'm an oddball in that regard.

freedomben 8y ago
I tend to agree with you, tho when I consider security of the 5G network I think more about large-scale disruptions due to compromise rather than targeting of individuals. Example scenario: War breaks out between two nations (such as the US and China, or US and Russia, or some other country). Cyber attack from enemy shuts down many if not all wireless communication. That would be a catastrophic disaster, and something that does seem like a legitimate defense consideration. That said, I tend to think that free and mutually dependent trade is a good solution here (basically the opposite of Trump's trade war). Going back to the ancients, the countries with the most trade are the least likely to engage in hostile acts. There's an old saying, "where goods cross borders, armies don't."
- mycall 8y ago
  This is where mesh networking comes into play for LWAN fallback.