Schlagwort-Archive: Signal

one of the key things that set SIGNAL MESSENGER apart—that it collects almost no information about its users, appears to be changing.

https://www.vice.com/en_us/article/pkyzek/signal-new-pin-feature-worries-cybersecurity-experts

Signal’s New PIN Feature Worries Cybersecurity Experts

The popular encrypted app is now going to store your contacts in the cloud. Experts are worried this compromises users’ privacy.

by Lorenzo Franceschi-Bicchierai
July 10, 2020, 2:33pm

Ever since NSA leaker Edward Snowden said “use Signal, use Tor,” the end-to-end encrypted chat app has been a favorite of people—including Motherboard—who care about privacy and need a chat and calling app that is hard to spy on.

One of the reasons security experts recommended Signal is because the app’s developers collected—and thus retained—almost no information about its users. This means that, if subpoenaed by law enforcement, Signal would have essentially nothing to turn over. Signal demonstrated this in 2016, when it was subpoenaed by a court in Virginia. „We’ve designed the Signal service to minimize the data we retain about Signal users, so the only information we can produce in response to a request like this is the date and time a user registered with Signal and the last date of a user’s connectivity to the Signal service,“ Signal wrote at the time.

But a newly added feature that allows users to recover certain data, such as contacts, profile information, settings, and blocked users, has led some high-profile security experts to criticize the app’s developers and threaten to stop using it. Signal will store that data on servers the company owns, protected by a PIN that the app has initially been asking users to add, and then forced them to.

The purpose of using a PIN is, in the near future, to allow Signal users to be identified by a username, as opposed to their phone number, as Signal founder Moxie Marlinspike explained on Twitter (as we’ve written before, this is a laudable goal; tying Signal to a phone number has its own privacy and security implications).

”Make the networks dumb and the clients smart.”
But this also means that unlike in the past, Signal now retains certain user data, something that many cybersecurity and cryptography experts see as too dangerous.

Matthew Green, a cryptographer and computer science professor at Johns Hopkins University, said that this was “the wrong decision,” and that forcing users to create a PIN and use this feature would force him to stop using the app.

“The problem with that is that most people pick weak PIN codes. To harden this and make the system more secure, Signal has a system that uses Intel SGX enclaves on their server,”Green said in an email to Motherboard, referring to a technology made by Intel to encrypt and isolate certain data on a cloud server. “SGX seems like a good choice, but it really can’t stand up against a serious attacker. This means anyone with the right resources (at least as good as, say, Daniel Genkin’s group and U. Mich) could potentially compromise those servers and get most of this information.”

“I don’t care that much about my contact lists, honestly. But I also don’t like the idea that I’m going to be forced into uploading them to a server, when the whole reason I use Signal is because it’s designed not to do things like this. Also, I’m scared that in the future, Moxie will design a feature to upload message content, and that won’t be ‚opt in‘ either,“ Green said.

Have you ever tried to hack Signal or look for vulnerabilities in the app? We’d love to hear from you. Using a non-work phone or computer, you can contact Lorenzo Franceschi-Bicchierai securely on Signal at +1 917 257 1382, OTR chat at lorenzofb@jabber.ccc.de, or email lorenzofb@vice.com
The Grugq, a well-known cybersecurity expert, agreed that this approach isn’t secure, because SGX enclaves are “a sort of wet paper bag for clustering sensitive info.”

Technical issues aside, it’s the philosophy behind it that bothers people like Green and The Grugq. Before this new feature, Signal claimed—and had proved—to provide a communication app that was designed not to store almost any information about its users.

„Notably, things we don’t have stored include anything about a user’s contacts (such as the contacts themselves, a hash of the contacts, any other derivative contact information), anything about a user’s groups (such as how many groups a user is in, which groups a user is in, the membership lists of a user’s groups), or any records of who a user has been communicating with,“ Signal wrote in 2016.

That, according to critics, has now changed.

“They should have a dumb network that knows nothing because it can’t be compromised then,” The Grugq told Motherboard. “[Having contacts] is a lot. It isn’t messages, sure. But I don’t like it. I don’t want them to have anything. Make the networks dumb and the clients smart.”

Marlinspike defended the decision to enable PINs and give users a way to migrate to a new device and keep certain data, and will increase the security of users’ metadata, “new features Signal users have been asking for.”

“The purpose of PINs is to enable upcoming features like communicating without sharing your phone number. When that is released, your Signal contacts won’t be able to live in the address book on your phone anymore, since they may not have phone numbers associated with them,” Marlinspike told Motherboard. “For most users, this also increases the security of their metadata. Most people’s address book is syncing with Google or Apple, so this change will prevent Google and Apple from having access to your Signal contacts.”

Following Green’s and others critiques, Marlinspike said on Twitter, and then confirmed with us, that Signal will add the ability to disable PINs “for some advanced users.’ Marlinspike warned that doing that “would mean that every time you re-install Signal you will lose all your Signal contacts.”

In recent weeks, Signal has introduced more features that make it more user friendly to people who may not have extremely paranoid threat models. For example, it’s now possible to migrate all Signal data, including message history, from one phone to another, using a feature that does not rely on cloud servers and is also encrypted, according to Signal. This is a different feature than the one that relies on PINs, but both of these are likely aimed at people who may be reluctant to use Signal, and prefer other apps such as WhatsApp.

The changes Signal has made show how there can be a tension between messenger usability and feature set and security. It’s too early to say whether you should stop using the messenger. For most users‘ threat models, it’s still one of the best options. But one of the key things that set Signal apart—that it collects almost no information about its users, appears to be changing.

Secure your Privacy – HERE’S WHY YOU SHOULD USE SIGNAL

Source: https://www.wired.com/story/ditch-all-those-other-messaging-apps-heres-why-you-should-use-signal/

STOP ME IF you’ve heard this before. You text a friend to finalize plans, anxiously awaiting their reply, only to get a message from them on Snapchat to say your latest story was hilarious. So, you move the conversation over to Snapchat, decide to meet up at 10:30, but then you close the app and can’t remember if you agreed on meeting at Hannegan’s or that poppin‘ new brewery downtown. You can’t go back and look at the message since Snapchat messages have a short shelf life, so you send a text, but your friend has already proven to be an unreliable texter. You’d be lucky if they got back to you by midnight.

All of this illustrates a plain truth. There are just too many messaging apps. As conversations can bounce between Snapchat, iMessage, Skype, Instagram, Twitter, and Hangouts/Allo or whatever Google’s latest attempt at messaging is, they’re rendered confusing and unsearchable. We could stick to SMS, but it’s pretty limited compared to other options, and it has some security holes. Rather than just chugging along with a dozen chat apps, letting your notifications pile up, it’s time to pick one messaging app and get all of your friends on board. That way, everyone can just pick up their phones and shoot a message to anyone without hesitation.

Here comes the easy part. There’s one messaging app we should all be using: Signal. It has strong encryption, it’s free, it works on every mobile platform, and the developers are committed to keeping it simple and fast by not mucking up the experience with ads, web-tracking, stickers, or animated poop emoji.

Tales From the Crypto

Signal looks and works a lot like other basic messaging apps, so it’s easy to get started. It’s especially convenient if you have friends and family overseas because, like iMessage and WhatsApp, Signal lets you sidestep expensive international SMS fees. It also supports voice and video calls, so you can cut out Skype and FaceTime. Sure, you don’t get fancy stickers or games like some of the competition, but you can still send pictures, videos, and documents. It’s available on iOS, Android, and desktop.

But plenty of apps have all that stuff. The thing that actually makes Signal superior is that it’s easy to ensure that the contents of every chat remain private and unable to be read by anyone else. As long as both parties are using the app to message each other, every single message sent with Signal is encrypted. Also, the encryption Signal uses is available under an open-source license, so experts have had the chance to test and poke the app to make sure it stays as secure as what’s intended.

If you’re super concerned about messages being read by the wrong eyes, Signal lets you force individual conversations to delete themselves after a designated amount of time. Signal’s security doesn’t stop at texts. All of your calls are encrypted, so nobody can listen in. Even if you have nothing to hide, it’s nice to know that your private life is kept, you know, private.

WhatAbout WhatsApp

Yes, this list of features sounds a lot like WhatsApp. It’s true, the Facebook-owned messaging app has over a billion users, offers most of the same features, and even employs Signal’s encryption to keep chats private. But WhatsApp raises a few concerns that Signal doesn’t. First, it’s owned by Facebook, a company whose primary interest is in collecting information about you to sell you ads. That alone may steer away those who feel Facebook already knows too much about us. Even though the content of your WhatsApp messages are encrypted, Facebook can still extract metadata from your habits, like who you’re talking to and how frequently.

Still, if you use WhatsApp, chances are you already know a lot of other people who are using it. Getting all of them to switch to Signal is highly unlikely. And you know, that’s OK—WhatsApp really is the next-best option to Signal. The encryption is just as strong, and while it isn’t as cleanly stripped of extraneous features as Signal, that massive user base makes it easy to reach almost anyone in your contact list.

Chat Heads

While we’re talking about Facebook, it’s worth noting that the company’s Messenger app isn’t the safest place to keep your conversations. Aside from all the clutter inside the app, the two biggest issues with Facebook Messenger are that you have to encrypt conversations individually by flipping on the „Secret Conversations“ option (good luck remembering to do that), and that anyone with a Facebook profile can just search for your name and send you a message. (Yikes!) There are too many variables in the app, and a lot the security is out of your hands. iMessage may seem like a solid remedy to all of these woes, but it’s tucked behind Apple’s walled iOS garden, so you’re bound to leave out your closest friends who use Android devices. And if you ever switch platforms, say bye-bye to your chat history.

Signal isn’t going to win a lot of fans among those who’ve grown used to the more novel features inside their chat apps. There are no stickers, and no animoji. Still, as privacy issues come to the fore in the minds of users, and as mobile messaging options proliferate, and as notifications pile up, everyone will be searching for a path to sanity. It’s easy to invite people to Signal. Once you’re using it, just tap the „invite“ button inside the chat window, and your friend will be sent a link to download the app. Even stubborn people who only send texts can get into it—Signal can be set as your phone’s default SMS client, so the pain involved in the switch is minimal.

So let’s make a pact right now. Let’s all switch to Signal, keep our messages private, and finally put an end to the untenable multi-app shuffle that’s gone on far too long.

Delete Signal’s texts, or the app itself, and virtually no trace of the conversation remains.

Delete Signal’s texts, or the app itself, and virtually no trace of the conversation remains. “The messages are pretty much gone

Suing to See the Feds’ Encrypted Messages? Good Luck

The recent rise of end-to-end encrypted messaging apps has given billions of people access to strong surveillance protections. But as one federal watchdog group may soon discover, it also creates a transparency conundrum: Delete the conversation from those two ends, and there may be no record left.

The conservative group Judicial Watch is suing the Environmental Protection Agency under the Freedom of Information Act, seeking to compel the EPA to hand over any employee communications sent via Signal, the encrypted messaging and calling app. In its public statement about the lawsuit, Judicial Watch points to reports that EPA staffers have used Signal to communicate secretly, in the face of an adversarial Trump administration.

But encryption and forensics experts say Judicial Watch may have picked a tough fight. Delete Signal’s texts, or the app itself, and virtually no trace of the conversation remains. “The messages are pretty much gone,” says Johns Hopkins crypotgrapher Matthew Green, who has closely followed the development of secure messaging tools. “You can’t prove something was there when there’s nothing there.”

End-to-Dead-End

Signal, like other end-to-end encryption apps, protects messages such that only the people participating in a conversation can read them. No outside observer—not even the Signal server that the messages route through—can sneak a look. Delete the messages from the devices of two Signal communicants, and no other unencrypted copy of it exists.

In fact, Signal’s own server doesn’t keep record of even the encrypted versions of those communications. Last October, Signal’s developers at the non-profit Open Whisper Systems revealed that a grand jury subpoena had yielded practically no useful data. “The only information we can produce in response to a request like this is the date and time a user registered with Signal and the last date of a user’s connectivity to the Signal service,” Open Whisper Systems wrote at the time. (That’s the last time they opened the app, not sent or received a message.)

Even seizing and examining the phones of EPA employees likely won’t help if users have deleted their messages or the full app, Green says. They could even do so on autopilot. Six months ago, Signal added a Snapchat-like feature to allow automated deletionof a conversation from both users’ phones after a certain amount of time. Forensic analyst Jonathan Zdziarski, who now works as an Apple security engineer, wrote in a blog post last year that after Signal messages are deleted, the app “leaves virtually nothing, so there’s nothing to worry about. No messy cleanup.” (Open Whisper Systems declined to comment on the Judicial Watch FOIA request, or how exactly it deletes messages.)

Still, despite its best sterilization efforts, even Signal might leave some forensic trace of deleted messages on phones, says Green. And other less-secure ephemeral messaging apps like Confide, which has also become popular among government staffers, likely leave more fingerprints behind. But Green argues that recovering deleted messages from even sloppier apps would take deeper digging than FOIA requests typically compel—so long as users are careful to delete messages on both sides of the conversation and any cloud backups. “We’re talking about expensive, detailed forensic analysis,” says Green. “It’s a lot more work than you’d expect from someone carrying out FOIA requests.”

For the Records

Deleting records of government business from government-issued devices is—let’s be clear—illegal. That smartphone scrubbing, says Georgetown Law professor David Vladeck, would blatantly violate the Federal Records Act. “It’s no different from taking records home and burning them,” says Vladeck. “They’re not your records, they’re the federal government’s, and you’re not supposed to do that.”

Judicial Watch, for its part, acknowledges that it may be tough to dig up deleted Signal communications. But another element of its FOIA request asks for any EPA information about whether it has approved Signal for use by agency staffers. “They can’t use these apps to thwart the Federal Records Act just because they don’t like Donald Trump,” says Judicial Watch president Tom Fitton. “This serves also as an educational moment for any government employees, that using the app to conduct government business to ensure the deletion of records is against the law, and against record-keeping policies in almost every agency.”

Fitton hopes the lawsuit will at least compel the EPA to prevent employees from installing Signal or similar apps on government-issued phones. “The agency is obligated to ensure their employees are following the rules so that records subject to FOIA are preserved,” he says. “If they’re not doing that, they could be answerable to the courts.”

Georgetown’s Vladeck says that even evidence employees have used Signal at all should be troubling, and might warrant a deeper investigation. “I would be very concerned if employees were using an app designed to leave no trace. That’s smoke, if not a fire, and it’s deeply problematic,” he says.

But Johns Hopkins’ Green counters that FOIA has never been an all-seeing eye into government agencies. And he points out that sending a Signal message to an EPA colleague isn’t so different from simply walking into their office and closing the door. “These ephemeral communications apps give us a way to have those face-to-face conversations electronically and in a secure way,” says Green. “It’s a way to communicate without being on the record. And people need that.”

https://www.wired.com/2017/04/suing-see-feds-encrypted-messages-good-luck/