cybergibbons

One of the big reasons I am here is to make sure anything I infer isn't false.

I don't recall any point where I haven't given enough evidence to back up a claim about a specific product. If I haven't named the product, it is because the manufacturer has made it clear they would be interested in legal action, so I need to be careful. The system that I didn't name that I don't think is good, I provided a document describing a similar system, and asked you to make your own conclusions. Open up a Scantronic wireless panel, look at that document, compare the radio modules, make your own judgement. I don't know. I'd question the use of the word "encryption" under trading standards. If your signalling system claimed it was encrypted and it turned out to be as weak as this, would that not be of concern?

Technically it's not encryption either. So, on a marketing and technical level, it's pretty bad. Where's the line? "This alarm uses rolling code" and the rolling code is 1,2,3,4. Is that dodgy? So if I am allowed chosen plaintext (i.e. I can call up the ARC and tell them whatever quote code I chose, and get a response), then it wouldn't require many pairs to get the keys. I don't know how possible this would be, as I think they would have to see an alarm activation, which means I would need a real quote/code pair. If it's only known plaintext (i.e. I am using valid quote codes generated by the alarm), it would be quite a lot more pairs required. Still a tiny number compared to the security a 2048-bit key affords. All of this would have been caught by an undergraduate doing a cryptography coursework "Is this homebrewed MAC secure?". It wouldn't have been hard to make this secure at all. Actually, I think it would be less effort just using something ready made.

How do I change that though? I've looked at a good few systems, enough that I can form an opinion of where they lie in terms of security. I've posted information on why I think the bad products are bad, some of which has been in quite a lot of depth. I can go into more depth, but as many have said, it would be beyond them. I can that installers aren't in possession of all the facts - there are alarm systems that fall far short of the marketing.

Absolutely nothing, it's marketing. It suggests it would be a standard that the military could use, which suggests it might pass some standards that the military have. If any of you have Technistore in front of you and it is a version where you can change the seed, try this: Seed 100, code 33333 Seed 101, code 22222 Seed 102, code 11111 Notice how they all produce the same unlock code? It's leaking information - changing outputs in a predictable way like this shouldn't produce a predictable output. I think, but I am not 100% sure, than it would only take about 50 valid reset/code pairs for me to determine the seed and the far longer initialisation vector (256 bytes). So even if the key was much longer, the algorithm sucks.

I don't think I have said that one brand is secure really, just my impression of it is better than others. Is it any different to an installer saying they prefer Texecom over Honeywell?

For Technistore, on average you need just one quote/reset code pair to derive the seed code. About 0.25% of code pairs lead to two valid seeds, and less than 0.01% generate more than that. So after a single reset, you have the seed for your panel, and it seems quite likely the seed for all alarms on the same ARC (correct me if wrong, there are quite a lot of references to the seed not varying on a per-customer basis). Like I say, the key length is so short that you can normally recover it with a single quote/reset code pair. No need to spy on the installer. So what if it isn't genuine? The point is that this mechanism is touted as secure ("a military strength data encryption algorithm") and it isn't. There isn't a need for it to be insecure, this is just bad code. Reverse engineering for the purposes of writing your own code for interoperability is specifically protected in law in the EU.

There's money in reverse engineering, trust me.

Which one is it then?

You'd still need a lot of skill from anything I had posted to be able to defeat the anti-codes. On one hand I am being told that these issues I'm pointing out aren't real vulnerabilities, on the other hand I'm being told that they shouldn't be published?

Changed to reset, sorry.

I've just updated the blog with my findings from the reverse engineering of Technistore, if anyone is interested.

The key would need to be longer than the pin for it to be difficult. With it being so short, it's really not hard.

Thanks, I guess?

So I guess I need to start ripping UDL software apart now?

Technistore and one other. Not wanting to name as I can't openly source it.

It's a hard one to make better though. If you are limited to 0-9 on 5 digits, it can only be so secure, but a seed at least as long as the reset code would make it better.

It's easy to bypass that check with a debugger, and then it just seems to be a 0-255 code.

That's interesting. With no seed, the only protection is keeping the executable secret. Technistore allow you to download it from their site, oddly.

This is the thing - it is virtually impossible to secure an executable such that you can't get the algorithm out. The security has to be in the key (the secret). If the key is only 8 bits, then guessing it isn't going to be hard. Have their been many changes in anti-codes recently? Do new panels have new decoders? Which standard or body is it that dictates how anti-codes are used?

Another question about impressions of security. I'm looking at anti-codes at the moment, which seem common on monitored systems. Typically this takes a 5 digit quote code along with a secret seed, and generates a 5 digit reset code (along these lines, anyway). It turns out for the few decoders I have now looked at, the secret seed can be determined from a one or two pairs of quote/reset codes. If this seed was constant across an entire installer or manufacturer, this could present a risk. What are your thoughts on this?

It doesn't take me much longer to get from West London to the NEC than getting to Excel, such is the public transport.