Entries Tagged "videoconferencing"

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Zoom Can Spy on Your Calls and Use the Conversation to Train AI, But Says That It Won’t

This is why we need regulation:

Zoom updated its Terms of Service in March, spelling out that the company reserves the right to train AI on user data with no mention of a way to opt out. On Monday, the company said in a blog post that there’s no need to worry about that. Zoom execs swear the company won’t actually train its AI on your video calls without permission, even though the Terms of Service still say it can.

Of course, these are Terms of Service. They can change at any time. Zoom can renege on its promise at any time. There are no rules, only the whims of the company as it tries to maximize its profits.

It’s a stupid way to run a technological revolution. We should not have to rely on the benevolence of for-profit corporations to protect our rights. It’s not their job, and it shouldn’t be.

Posted on August 15, 2023 at 7:03 AMView Comments

Leaking Screen Information on Zoom Calls through Reflections in Eyeglasses

Okay, it’s an obscure threat. But people are researching it:

Our models and experimental results in a controlled lab setting show it is possible to reconstruct and recognize with over 75 percent accuracy on-screen texts that have heights as small as 10 mm with a 720p webcam.” That corresponds to 28 pt, a font size commonly used for headings and small headlines.

[…]

Being able to read reflected headline-size text isn’t quite the privacy and security problem of being able to read smaller 9 to 12 pt fonts. But this technique is expected to provide access to smaller font sizes as high-resolution webcams become more common.

“We found future 4k cameras will be able to peek at most header texts on almost all websites and some text documents,” said Long.

[…]

A variety of factors can affect the legibility of text reflected in a video conference participant’s glasses. These include reflectance based on the meeting participant’s skin color, environmental light intensity, screen brightness, the contrast of the text with the webpage or application background, and the characteristics of eyeglass lenses. Consequently, not every glasses-wearing person will necessarily provide adversaries with reflected screen sharing.

With regard to potential mitigations, the boffins say that Zoom already provides a video filter in its Background and Effects settings menu that consists of reflection-blocking opaque cartoon glasses. Skype and Google Meet lack that defense.

Research paper.

Posted on September 23, 2022 at 6:43 AMView Comments

Video Conferencing Apps Sometimes Ignore the Mute Button

New research: “Are You Really Muted?: A Privacy Analysis of Mute Buttons in Video Conferencing Apps“:

Abstract: In the post-pandemic era, video conferencing apps (VCAs) have converted previously private spaces—bedrooms, living rooms, and kitchens—into semi-public extensions of the office. And for the most part, users have accepted these apps in their personal space, without much thought about the permission models that govern the use of their personal data during meetings. While access to a device’s video camera is carefully controlled, little has been done to ensure the same level of privacy for accessing the microphone. In this work, we ask the question: what happens to the microphone data when a user clicks the mute button in a VCA? We first conduct a user study to analyze users’ understanding of the permission model of the mute button. Then, using runtime binary analysis tools, we trace raw audio in many popular VCAs as it traverses the app from the audio driver to the network. We find fragmented policies for dealing with microphone data among VCAs—some continuously monitor the microphone input during mute, and others do so periodically. One app transmits statistics of the audio to its telemetry servers while the app is muted. Using network traffic that we intercept en route to the telemetry server, we implement a proof-of-concept background activity classifier and demonstrate the feasibility of inferring the ongoing background activity during a meeting—cooking, cleaning, typing, etc. We achieved 81.9% macro accuracy on identifying six common background activities using intercepted outgoing telemetry packets when a user is muted.

The paper will be presented at PETS this year.

News article.

Posted on April 29, 2022 at 9:18 AMView Comments

Zoom Lied about End-to-End Encryption

The facts aren’t news, but Zoom will pay $85M—to the class-action attorneys, and to users—for lying to users about end-to-end encryption, and for giving user data to Facebook and Google without consent.

The proposed settlement would generally give Zoom users $15 or $25 each and was filed Saturday at US District Court for the Northern District of California. It came nine months after Zoom agreed to security improvements and a “prohibition on privacy and security misrepresentations” in a settlement with the Federal Trade Commission, but the FTC settlement didn’t include compensation for users.

Posted on August 5, 2021 at 6:25 AMView Comments

Zoom Will Be End-to-End Encrypted for All Users

Zoom is doing the right thing: it’s making end-to-end encryption available to all users, paid and unpaid. (This is a change; I wrote about the initial decision here.)

…we have identified a path forward that balances the legitimate right of all users to privacy and the safety of users on our platform. This will enable us to offer E2EE as an advanced add-on feature for all of our users around the globe—free and paid—while maintaining the ability to prevent and fight abuse on our platform.

To make this possible, Free/Basic users seeking access to E2EE will participate in a one-time process that will prompt the user for additional pieces of information, such as verifying a phone number via a text message. Many leading companies perform similar steps on account creation to reduce the mass creation of abusive accounts. We are confident that by implementing risk-based authentication, in combination with our current mix of tools—including our Report a User function—we can continue to prevent and fight abuse.

Thank you, Zoom, for coming around to the right answer.

And thank you to everyone for commenting on this issue. We are learning—in so many areas—the power of continued public pressure to change corporate behavior.

EDITED TO ADD (6/18): Let’s do Apple next.

Posted on June 17, 2020 at 1:55 PMView Comments

Zoom's Commitment to User Security Depends on Whether you Pay It or Not

Zoom was doing so well…. And now we have this:

Corporate clients will get access to Zoom’s end-to-end encryption service now being developed, but Yuan said free users won’t enjoy that level of privacy, which makes it impossible for third parties to decipher communications.

“Free users for sure we don’t want to give that because we also want to work together with FBI, with local law enforcement in case some people use Zoom for a bad purpose,” Yuan said on the call.

This is just dumb. Imagine the scene in the terrorist/drug kingpin/money launderer hideout: “I’m sorry, boss. We could have have strong encryption to secure our bad intentions from the FBI, but we can’t afford the $20.” This decision will only affect protesters and dissidents and human rights workers and journalists.

Here’s advisor Alex Stamos doing damage control:

Nico, it’s incorrect to say that free calls won’t be encrypted and this turns out to be a really difficult balancing act between different kinds of harms. More details here:

Some facts on Zoom’s current plans for E2E encryption, which are complicated by the product requirements for an enterprise conferencing product and some legitimate safety issues. The E2E design is available here: https://github.com/zoom/zoom-e2e-whitepaper/blob/master/zoom_e2e.pdf

I read that document, and it doesn’t explain why end-to-end encryption is only available to paying customers. And note that Stamos said “encrypted” and not “end-to-end encrypted.” He knows the difference.

Anyway, people were rightly incensed by his remarks. And yesterday, Yuan tried to clarify:

Yuan sought to assuage users’ concerns Wednesday in his weekly webinar, saying the company was striving to “do the right thing” for vulnerable groups, including children and hate-crime victims, whose abuse is sometimes broadcast through Zoom’s platform.

“We plan to provide end-to-end encryption to users for whom we can verify identity, thereby limiting harm to vulnerable groups,” he said. “I wanted to clarify that Zoom does not monitor meeting content. We do not have backdoors where participants, including Zoom employees or law enforcement, can enter meetings without being visible to others. None of this will change.”

Notice that is specifically did not say that he was offering end-to-end encryption to users of the free platform. Only to “users we can verify identity,” which I’m guessing means users that give him a credit card number.

The Twitter feed was similarly sloppily evasive:

We are seeing some misunderstandings on Twitter today around our encryption. We want to provide these facts.

Zoom does not provide information to law enforcement except in circumstances such as child sexual abuse.

Zoom does not proactively monitor meeting content.

Zoom does no have backdoors where Zoom or others can enter meetings without being visible to participants.

AES 256 GCM encryption is turned on for all Zoom users—free and paid.

Those facts have nothing to do with any “misunderstanding.” That was about end-to-end encryption, which the statement very specifically left out of that last sentence. The corporate communications have been clear and consistent.

Come on, Zoom. You were doing so well. Of course you should offer premium features to paying customers, but please don’t include security and privacy in those premium features. They should be available to everyone.

And, hey, this is kind of a dumb time to side with the police over protesters.

I have emailed the CEO, and will report back if I hear back. But for now, assume that the free version of Zoom will not support end-to-end encryption.

EDITED TO ADD (6/4): Another article.

EDITED TO ADD (6/4): I understand that this is complicated, both technically and politically. (Note, though, Jitsi is doing it.) And, yes, lots of people confused end-to-end encryption with link encryption. (My readers tend to be more sophisticated than that.) My worry that the “we’ll offer end-to-end encryption only to paying customers we can verify, even though there’s plenty of evidence that ‘bad purpose’ people will just get paid accounts” story plays into the dangerous narrative that encryption itself is dangerous when widely available. And I disagree with the notion that the possibility of child exploitation is a valid reason to deny security to large groups of people.

Matthew Green on this issue. An excerpt:

Once the precedent is set that E2E encryption is too “dangerous” to hand to the masses, the genie is out of the bottle. And once corporate America accepts that private communications are too politically risky to deploy, it’s going to be hard to put it back.

From Signal:

Want to help us work on end-to-end encrypted group video calling functionality that will be free for everyone? Zoom on over to our careers page….

Posted on June 4, 2020 at 6:24 AMView Comments

Securing Internet Videoconferencing Apps: Zoom and Others

The NSA just published a survey of video conferencing apps. So did Mozilla.

Zoom is on the good list, with some caveats. The company has done a lot of work addressing previous security concerns. It still has a bit to go on end-to-end encryption. Matthew Green looked at this. Zoom does offer end-to-end encryption if 1) everyone is using a Zoom app, and not logging in to the meeting using a webpage, and 2) the meeting is not being recorded in the cloud. That’s pretty good, but the real worry is where the encryption keys are generated and stored. According to Citizen Lab, the company generates them.

The Zoom transport protocol adds Zoom’s own encryption scheme to RTP in an unusual way. By default, all participants’ audio and video in a Zoom meeting appears to be encrypted and decrypted with a single AES-128 key shared amongst the participants. The AES key appears to be generated and distributed to the meeting’s participants by Zoom servers. Zoom’s encryption and decryption use AES in ECB mode, which is well-understood to be a bad idea, because this mode of encryption preserves patterns in the input.

The algorithm part was just fixed:

AES 256-bit GCM encryption: Zoom is upgrading to the AES 256-bit GCM encryption standard, which offers increased protection of your meeting data in transit and resistance against tampering. This provides confidentiality and integrity assurances on your Zoom Meeting, Zoom Video Webinar, and Zoom Phone data. Zoom 5.0, which is slated for release within the week, supports GCM encryption, and this standard will take effect once all accounts are enabled with GCM. System-wide account enablement will take place on May 30.

There is nothing in Zoom’s latest announcement about key management. So: while the company has done a really good job improving the security and privacy of their platform, there seems to be just one step remaining to fully encrypt the sessions.

The other thing I want Zoom to do is to make the security options necessary to prevent Zoombombing to be made available to users of the free version of that platform. Forcing users to pay for security isn’t a viable option right now.

Finally—I use Zoom all the time. I finished my Harvard class using Zoom; it’s the university standard. I am having Inrupt company meetings on Zoom. I am having professional and personal conferences on Zoom. It’s what everyone has, and the features are really good.

Posted on April 30, 2020 at 10:24 AMView Comments

Sidebar photo of Bruce Schneier by Joe MacInnis.