So it's a classic tradeoff - convenience vs. security, and the Guardian story correctly reported it.
> and WhatsApp offers people security notifications to alert them to potential security risks.
which is not enabled by default.
Sounds to me like apart from the hyperbolic use of the word "backdoor" (which apparently has now been removed), The Guardian is in the clear here.
The Guardian needs to retract and sanction its editor. The story is journalistic malpractice and puts people at risk.
This is not about word use, but about publishing stories that are already causing people in high-risk places to move off of a secure messenger to SMS.
Signal doesn't make that bad trade-off, for example. There are viable alternatives.
There's empirical evidence that people switch off to SMS. In places like Egypt, people share phones, swap SIM cards routinely, and Signal's nondelivery behavior is a non-starter. Zeynep does research on this and has written a lot about it; it's fascinating (and depressing) reading.
The point is that these are not hypothetical scare scenarios. We have the data and that's why it's so urgent to chastise this kind of reckless coverage.
The only message those people are getting is "WHATSAPP BAD, SWITCH". And switch they are, but not to Signal (none of their friends on are on Signal). Nope, they're adopting insecure alternatives, where they can actually talk to their peers.
The flaw is as follows: I'm trying to send you a message, but your phone is offline and lost. When you get a new phone, your key has changed, but WhatsApp will deliver my message before informing me of the key change. This applies also to calls and such (which shouldn't be "delivered" if the other person is offline).
Why could this be bad? WhatsApp could exploit it as follows (maybe under orders from the govt.):
1) Make it seem like a user lost their phone.
2) Wait for a message to be delivered to the user's account.
3) Bring the user back online with a new key (generated by WhatsApp themselves).
4) Read the "encrypted" message.
It's a real vulnerability in the protocol, but the severity depends on your threat model. As I said above, this might be an acceptable trade off for messaging, but not for things like calls, where if the user is offline you don't want the call to go through anyway. All this has been pointed out clearly by the student who discovered it.
Making Signal show white-on-white text would make it more secure against attackers reading over your shoulder. So why doesn't Signal do that?
These are legitimate trade-offs that the Guardian is portraying as vulnerabilities.
Anyway, I don't think it's a reasonable choice. How any times do people change phones?!? Even if you're rich you don't do that more than once a year. It doesn't happen often enough for the user to become "accustomed" to warnings and simply click through them.
But you don't, because shoulder surfing is not the threat model for Signal. And individually targeted MITM attacks by governments that can take over a server are not the threat model for WhatsApp.
If it even works to enhance the privacy of 0.1% of users, it's helped a million people in ways that SMS has not.
I see all these people come in defense of WhatsApp using bizarre statistics about domestic violence (big correlation with hacking?). Then someone (tptacek?) was going around saying not a single crypto expert disagrees with their consensus (trucking all over the original source, Tobias Boelter). Then there are all these jokey "Is WhatsApp Backdoored Yet?" expressions. It's a frenzy.
There seem to be a whole bunch of people who take The Guardian article as "omg, after this article, people will drop WhatsApp and use something like Messenger instead!". Which, sure enough, maybe a common scenario, and worse. However, the article was obviously meant to push people outside of Facebook gardens, and into a more secure alternative. It's supposed to make you go "WhatsApp is unsafe, I will use Signal instead". One of those "trade-offs" you're talking about in the first place, just like the security vs. purity one. In this case, erring on the side of activism.
As a sideline observer with very little crypto knowledge, I think Boelter presented an interesting case, while the anti-Guardian crowd reacted like crazy people, pulling fire alarms, hurling insults, and Streisand-effect-ing the story into a huge controversy.
I mean, the EFF article itself, in defense of WhatsApp and against The Guardian, says:
https://www.eff.org/deeplinks/2017/01/google-launches-key-tr...
> If you are a high-risk user whose safety might be compromised by a single revealed message, you may want to consider alternative applications. As we mention in our Surveillance Self-Defense guides for Android and iOS, we don't currently recommend WhatsApp for secure communications.
It goes on to qualify this statement by saying that's a rare threat model. However, that right there, is enough to justify the original piece. The idea, I think, is that everyone should be on something like Signal, so that merely using Signal wouldn't be taken as a reason for suspicion. If you disagree, your argument could surely be better than jokes about white text.
Just my two cents as a nobody.
Honestly, would a 'recipient key changed; resend message?' be the worst prompt in the world?
Referrence to a clear demonstration of a security vulburability in the protocol as a lie, is a demonstrably false statement
Asking the proverbial Johnny to make a security decision each time happens will result in alert fatigue. The overwhelming majority of users will always accept the new key because they just want the app to work.
They are not a magical panacea that makes MitM attacks go away. There are two good solutions to this for users who care, however:
- Verify keys with each other in person
- Move to Key Transparency / CONIKS-like systems for auditing key serversIt's interesting that you make this comparison. For a while now I've been of the position that web browsers should scrap all TLS user interface stuff (padlocks, green bars, invalid cert warnings, self signed cert warnings etc), because it doesn't communicate any information that the average user can make any use of.
It's only one aspect of what makes a site 'secure' for users, and probably one of the far less important ones. The vast majority of attacks on users (info being stolen, malware being served etc) come from the site itself being compromised, not from MitM attacks by their ISP. The vast majority of warnings about bad certs are due to somebody forgetting to update it or config issues, not because of real MitM attacks. The vast majority of people just click through cert warnings. The padlock icon in the browser doesn't even do the one thing it promises since it's no guarantee that TLS is being applied all the way to the actual web server. XSS is a bigger threat to the average user but browsers don't warn about sites that aren't using CSP.
My theory is that browser devs always knew the padlock icon was bullshit snake oil, but they implemented it at the demand of the e-commerce industry. At the time it was difficult to get people to trust the web enough to enter their credit card details. Providing a meaningless 'security' icon was needed to bootstrap consumer trust in the industry.
The green EV certificate stuff is what's supposed to tell you that you're safe from MitM and phishing, because you can verify the legal identity of the entity you're talking to.
Really the biggest problem is browsers like Chrome that use green padlock/text for DV certs, because that's misleading and either makes people trust the DV certs more than they should, or distrust EV certs. Safari does this much better, using a grey padlock (and no other text) for DV certs, and showing Green padlock + green text for EV certs.
https://www.theguardian.com/technology/2017/jan/13/whatsapp-...
And the "Should I stop using WhatsApp?" section is basically exactly what the letter is railing against.
Implement something for their benefit and the masses who don't care. When called out point to an a setting somewhere and call it a non-issue, "you can turn this on if you care". So they do what they want and can easily deflect all criticism. Facebook is not the first here and certainly not the last.