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Multiple Russia-aligned threat actors actively targeting Signal Messenger

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Re: Multiple Russia-aligned threat actors actively targeting Signal Messenger

#281

Post by BrenBarn »

parhamn wrote: post #216

One thing I'm realizing more and more (I've been building an encrypted AI chat service which is powered by encrypted CRDTs) is that "E2E encryption" really requires the client to be built and verified by the end user. I mean end of the day you can put a one-line fetch/analytics-tracker/etc on the rendering side and everything your protocol claimed to do becomes useless. That even goes further to the OS that the rende…

I agree with you that the cart seems to be moving ahead of the horse, in that there is an increasing fixation on the theoretical status of the encryption scheme rather than the practical risk of various outcomes. An important facet of this is that systems that attempt to be too secure will prevent users from reading their own messages and hence will induce those users to use "less secure" systems. (This has been a problem on Matrix, where clients have often not clearly communicated to users that logging out can result in permanently missed messages.)

There's a part of me that wonders whether some of the more hardcore desiderata like perfect forward secrecy are, in practical terms, incompatible with what users want from messaging. What users want is "I can see all of my own messages whenever I want to and no one else can ever see any of them." This is very hard to achieve. There is a fundamental tension between "security" and things like password resets or "lost my phone" recovery.

I think if people fully understood the full range of possible outcomes, a fair number wouldn't actually want the strongest E2EE protection. Rather, what they want are promises on a different plane, such as ironclad legal guarantees (an extreme example being something like "if someone else looks at my messages they will go to jail for life"). People who want the highest level of technical security may have different priorities, but designing the systems for those priorities risks a backlash from users who aren't willing to accept those tradeoffs.

Re: Multiple Russia-aligned threat actors actively targeting Signal Messenger

#282

Post by BrenBarn »

mmooss wrote: post #171
BrenBarn wrote: post #166

Is this suggesting that a single QR scan can on its own perform the device linking? If so, it seems like that's kind of the hole here, right? Like you shouldn't be able to scan a code that on its own links the device; you should have to manually confirm with like "Yes I want to link to this device". And then if you thought you were scanning a group invite code you'd realize you weren't. (Yeah, you'd still have to rea…

> you should have to manually confirm with like "Yes I want to link to this device". And then if you thought you were scanning a group invite code you'd realize you weren't. (Yeah, you'd still have to realize that, but I think it's a meaningful step up over just "you scanned a code to join a group and instead it silently linked a different device".) Remember that Signal is designed for non-technical users. Many/most…

> Do you have reason to think there is not confirmation?

The reason is just that in the article it says:

> threat actors have resorted to crafting malicious QR codes that, when scanned, will link a victim's account to an actor-controlled Signal instance

That phrasing suggests to me that the scanning of the QR code, on its own, performs the linking. That may not be the case, but if so I'd say the wording is misleading or at least imprecise.

Re: Multiple Russia-aligned threat actors actively targeting Signal Messenger

#284

Post by Cyphase »

BrenBarn wrote: post #281
parhamn wrote: post #216

One thing I'm realizing more and more (I've been building an encrypted AI chat service which is powered by encrypted CRDTs) is that "E2E encryption" really requires the client to be built and verified by the end user. I mean end of the day you can put a one-line fetch/analytics-tracker/etc on the rendering side and everything your protocol claimed to do becomes useless. That even goes further to the OS that the rende…

I agree with you that the cart seems to be moving ahead of the horse, in that there is an increasing fixation on the theoretical status of the encryption scheme rather than the practical risk of various outcomes. An important facet of this is that systems that attempt to be too secure will prevent users from reading their own messages and hence will induce those users to use "less secure" systems. (This has been a pr…

At a casual glance, any E2EE system can be reduced to your ironclad legally guaranteed (ILG) system by having the platform keep a copy of the key(s), for instance. So it doesn't have to be a one-or-the-other choice.

Re: Multiple Russia-aligned threat actors actively targeting Signal Messenger

#285

Post by nikolay »

wiseowise wrote: post #280
nikolay wrote: post #255

[flagged]

Bulgarian gypsies (what?) didn’t start a war against Germany, Nikolay.

It's the principle. Germans started the most destructive war in human history, but they are not vilified as much as the Russians!

Re: Multiple Russia-aligned threat actors actively targeting Signal Messenger

#286

Post by inor0gu »

vlovich123 wrote: post #271
inor0gu wrote: post #188

Earlier quoted context omitted.

Your phone (primary device) and the linked ones have to share the IK since that is the "root of trust" for you account: with that you generate new device keys, renew them and so on. Those keys are backed by Keystore on Android, and some similar system on Windows/Linux, i'd assume the same for MacOS/iOS (but I don't know the details) so it's not as simple as just having access to your laptop, they'd need at least root…

I think the point is that as a user you expect revocation of trust to protect you going forward, yet it doesn’t (e.g. the server shouldn’t be forwarding new messages to). That’s a design decision Signal made but clearly it’s one that leaves you open to harm. Moreover, it’s a dangerous decision because after obtaining the IK in some way (e.g. stolen device) you’re able to then essentially surreptitiously take over the…

Revocation of trust is always a tricky issue, you can look at TLS certificates to see what a can of worms that is.

The Signal server does not forward messages to your devices, and the list of devices someone has (including your own) can and has to be queried to communicate with them, since each device will establish unique keys signed by that IK, so it isn't as bad as having invisible devices that you'd never aware of. That of course relies on you being able to ensure the server is honest, and consistent, but this is already work in progress they are doing.

I think most of the issue here doesn't lie in the protocol design but in (1) how you "detect" the failure scenarios (like here, if your phone is informed a new device was added, without you pressing the Link button, you can assume something's phishy), (2) how do you properly warn people when something bad happens and (3) how do you inform users such that you both have a similar mental model. You also have to achieve these things without overwhelming them.

Re: Multiple Russia-aligned threat actors actively targeting Signal Messenger

#287

Post by solarkraft »

parhamn wrote: post #216

One thing I'm realizing more and more (I've been building an encrypted AI chat service which is powered by encrypted CRDTs) is that "E2E encryption" really requires the client to be built and verified by the end user. I mean end of the day you can put a one-line fetch/analytics-tracker/etc on the rendering side and everything your protocol claimed to do becomes useless. That even goes further to the OS that the rende…

> "E2E encryption" really requires the client to be built and verified by the end user

We probably agree that this is infeasible for the vast majority of people.

Luckily reproducible builds somewhat sidestep this in a more practical way.

Re: Multiple Russia-aligned threat actors actively targeting Signal Messenger

#288

Post by codethief »

XorNot wrote: post #269
mmooss wrote: post #44

Earlier quoted context omitted.

Is this serious? It raises questions about smartphones being standard equipment for soldiers, but they do give every soldier an effective, powerful computing and communication platform (that they know without additional training). The question is how to secure them, including against the risk described in the parent. That seems like a high risk to me I would expect someone is working on how to secure them enough that…

A radio on a soldier is already a dangerous communications device - with a radio you can call in artillery strikes, for example. There's no particular need IMO to secure smartphones on the battlefield in anyway beyond standard counter-measures - i.e. encrypt the storage, use a passcode unlock.

The Russian military would beg to differ, see the sibling's comment: https://news.ycombinator.com/item?id=43106162

Re: Multiple Russia-aligned threat actors actively targeting Signal Messenger

#289

Post by aembleton »

> In each of the fake group invites, JavaScript code that typically redirects the user to join a Signal group has been replaced by a malicious block containing the Uniform Resource Identifier (URI) used by Signal to link a new device to Signal (i.e., "sgnl://linkdevice?uuid="), tricking victims into linking their Signal accounts to a device controlled by UNC5792.

Missing from their recommendations: Install No Script: https://noscript.net/

Re: Multiple Russia-aligned threat actors actively targeting Signal Messenger

#290

Post by codethief »

baq wrote: post #59
retrochameleon wrote: post #51

Earlier quoted context omitted.

Awful shortsighted and uninformed viewpoint that has been beaten into the ground ad nauseum. Read a couple books. Privacy is a precondition to democracy.

It isn't a viewpoint. It's a fact. I'm using signal for almost a decade now and only managed to get a dozen or so people to use it in any capacity. Most keep using whatsapp as their primary method of communication anyway.

Meanwhile, I have been using Signal since the TextSecure days, too, and practically all my contacts are using it these days.
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