Gemalto's findings of its investigations into the alleged hacking of SIM cards

3G/4G somehow uses random, short lived keys for encrypted communication, which change frequently enough to be a pain.

EDIT: It has been a while since I studied this, but I believe the shared key is used for trust - that this isn't a fake base station and the client is who they say they are. Then they use the equivalent of public key cryptography to establish short lived encryption keys. Stealing keys would probably enable a MitM only?

Sorry for being OT, but maybe HN should recheck whether downvoting a comment just to express disagreement about a factual statement (as opposed to punishing bad or trollish ones) is conducive to a civil and constructive discourse here.

Their protection is that many MNOs are using proprietary authentication algorithms, making it harder to scale global surveillance. But that applies equally to 2G/3G/4G.

You can very cheaply(~$100) buy a 2G/3G/4G jammer from any Chinese wholesaler site(but don't,because it's illegal pretty much everywhere). Most of these jammers have a switch to jam only 3G and 4G, leaving 2G functional - that would force the phone you are attacking to switch to 2G mode as it couldn't find any 3G/4G towers.

Now, while this is true, I believe that a bad actor can still listen to the radio transmissions passively and decrypt those. But that is a lot harder than just plugging in to the tower and listening.

So whilst it would be possible to decrypt phone connections if you had your hands on the original secret Ki stored in the SIM, you'd have to record every connection between the phone and the network in order to obtain all the subsequent keys as well & if you miss out on the initial sign-on, or any individual re-keying then you’ll be shut out of that phone’s radio communications thereafter.

I imagine the NSA would be willing to try and do this for some target networks, but where they already have internal network access (US/UK/Five Eyes, any other network they've hacked into) it would be a lot of pointless effort.

The fake base station attack presumably works by forcing a downgrade to 2G, which is another approach, but one that requires local assets on the ground within phone range (unless you can do something with high gain antennas pointed at a specific target phone from a distance? That sounds hard, but the NSA likes hard as we know - throwing resources at something isn’t a problem for them.)

No kidding, they've been bought, under more-than-suspicious circumstances, by [inQtel](https://www.iqt.org/) and [Texas Partner Group](https://tpg.com/), which officially are CIA proxies.

I don't think they had to resort to tailored access to perform their heist, I'd rather bet that they still have enough former colleagues inside Gemalto to get whatever they want by simply entering the correct password on the correct keyboard.

Its a little disturbing that the "sophisticated" attacks they detected don't really sound all that sophisticated. Is spoofing an email and sending a PDF/Office exploit really considered sophisticated? While its a step above the most basic script-kiddie type stuff, that isn't unreasonable for even normal pentesting to do, and I wouldn't consider it an indicator of a nation-state attacker at all. Even if the attack was using 0-day in the attachment viewer, its not unheard of for malware kits to employ similar techniques.

It definitely says something that those attacks were at least partially successful against systems Gemalto thinks could have resulted in the theft of sensitive crypto keys.

That's a bit unfair. Gemalto say:

- "The risk of the data being intercepted as it was shared with our customers was greatly reduced with the generalization of highly secure exchange processes that we had put in place well before 2010."

- "The report... also states that when operators used secure data exchange methods the interception technique did not work."

- "Gemalto has never sold SIM cards to four of the twelve operators listed in the documents, in particular to the Somali carrier where a reported 300,000 keys were stolen."

- "A list claiming to represent the locations of our personalization centers shows SIM card personalization centers in Japan, Colombia and Italy. However, we did not operate personalization centers in these countries at the time."

There's a lot of valid points in Gemalto's report, and it seems dishonest to write it off so pettily.

A bit surprising they promote security by obscurity though:

"Security is even higher for mobile operators who work with Gemalto to embed custom algorithms in their SIM cards. The variety and fragmentation of algorithmic technologies used by our customers increases the complexity and cost to deploy massive global surveillance systems."

If you had to force cell phone connections to A5/0, you would have to:

1) Have to both receive and transmit.

2) Have a stronger connection than any other nearby cell towers.

3) Have a backbone connection back into the network so that you can actually negotiate phone calls to users connected to other cell phone towers.

4) Have to be able to handle multiple simultaneous connections. Some MITM spoof cell towers only establish a connection for the person of interest, and all other devices in the area loses connection. A pretty tell tale sign of a rogue base station operating in an area.

So in short it is much easier just to have the keys...