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Vulnerability in the Mac Zoom client allows malicious websites to enable camera

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Re: Vulnerability in the Mac Zoom client allows malicious websites to enable camera

#41

The article’s actual title is: Zoom Zero Day: 4+ Million Webcams & maybe an RCE? Just get them to visit your website! But, assuming I’m reading it correctly, the “maybe an RCE?” part seems like fear-mongering, because it would require that Zoom lose control of one of the domains that they trust for transparent client installs/upgrades. I’m also a little concerned about how some parts of the article don’t match up. Fo…

Dangling domains happen all the time. As long as the main one that's actually used is still controlled by the org, others can quite easily slip through the cracks, not renewed while still present in the codebase.

Re: Vulnerability in the Mac Zoom client allows malicious websites to enable camera

#42
post #30

> This vulnerability leverages the amazingly simple Zoom feature where you can just send anyone a meeting link (for example https://zoom.us/j/492468757 ) and when they open that link in their browser their Zoom client is magically opened on their local machine. I was curious about how this amazing bit of functionality was implemented and how it had been implemented securely. Come to find out, it really hadn’t been im…

below down the post, zoom team said that this feat exists because Safari doesn’t have custom url scheme.

I've opened up Safari and it properly asks me if I want to open slack when using: slack://test

Re: Vulnerability in the Mac Zoom client allows malicious websites to enable camera

#44

> This vulnerability leverages the amazingly simple Zoom feature where you can just send anyone a meeting link (for example https://zoom.us/j/492468757 ) and when they open that link in their browser their Zoom client is magically opened on their local machine. I was curious about how this amazing bit of functionality was implemented and how it had been implemented securely. Come to find out, it really hadn’t been im…

The basic problem is that you enter a meeting by loading a URL, and loading URLs is something any website can do. There probably needs to be a confirmation step before joining a meeting.

Re: Vulnerability in the Mac Zoom client allows malicious websites to enable camera

#45
post #38

How do you recommend uninstalling this?

From the article:

> To shut down the web server, run lsof -i :19421 to get the PID of the process, then do kill -9 [process number]. Then you can delete the ~/.zoomus directory to remove the web server application files.

> To prevent this server from being restored after updates you can execute the following in your terminal:

rm -rf ~/.zoomus

touch ~/.zoomus

Re: Vulnerability in the Mac Zoom client allows malicious websites to enable camera

#47
post #5

Note: "Zoom" is a videoconfrerencing app, not a built-in Mac OS accessibility feature for "zoom". The article does not clearly state this, ceding a plain English word to a corporation, enabling a takeover of human language. P.S.: This part > Apr 26, 2019 — Video call with Mozilla and Zoom Security Teams is funny, and would be way funnier if it was an non-consensual video call. Finally, note that Zoom effectively does…

Finally, note that Zoom effectively does not pay for bug bounties, so researchers should think twice about donating their expertise to a selfish for-profit corporation

I've read this a few times and am curious if this has really become the prevailing view about what security researchers are doing (i.e., uncompensated labor) when they notify vendors about security vulnerabilities.

The traditional view (which I think was widespread in the 90s or whatever) was that engineers who find vulnerabilities in products have a special responsibility to the public, and owe a duty to the people at risk: the users of the product (or whoever would be harmed if the vulnerability were exploited to malicious ends). Just like if you used your training as an engineer to discover that the Bay Bridge had a structural flaw and that drivers were at risk (or, in the case of Diane Hartley, that the new Citicorp Center had a design flaw and officeworkers were at risk). And this duty can be discharged a few ways, but often the most efficient way to help the people at risk is to educate the vendor and keep on their ass until they fix the problem in a free update. If the vendor pays you, fantastic, but you shouldn't accept payment that would prevent you from discharging your duty to the people actually harmed by the vulnerability's existence (e.g., if you take the vendor's money and it comes with an indefinite NDA, and they never fix the problem and the users remain at risk of being harmed by bad actors forever, you have not behaved acceptably as an engineer). This view probably emerged at a time when bug-finders mostly had salaried jobs and were privileged not to have to depend on payments from the same vendors they were annoying with information on their product's flaws.

A newer view (probably informed by bug bounties, etc., and also a broader community of people doing this stuff) seems to "no more free bugs for software vendors" -- that researchers who find vulnerabilities in commercial products are producing knowledge that's of value to the vendor, and the vendor ought to give them compensation for it, and if the vendor doesn't want to do that, the researcher would basically just be doing uncompensated labor to give it to the vendor, and is free to go sell the fruits of their discovery to somebody who does value their labor instead. Even if that means selling the bug to unknown counterparties at auction and signing a forever NDA not to tell anybody else.

The first view is mostly what we teach students in Stanford's undergrad computer-ethics course and what I think is consistent with the rest of the literature on engineering ethics (and celebrated examples like Diane Hartley and William LeMessurier, etc.), but I do think it seems to be out-of-step with the prevailing view among contemporary vuln-finders. I'd love to find some reading where this is carefully discussed that we could assign students.

Re: Vulnerability in the Mac Zoom client allows malicious websites to enable camera

#48
post #8

as demonstrated, "responsible disclosure" is a huge time waster for the discovery, and the price of this is undervalued even if the company had a clear bug bounty program. its more valuable than 90-days of a developer's time, not even correlated to time at all really

I guess this depends on your definition of responsible. Something like this however is bad enough that users should be informed right away so that they can take steps necessary to secure themselves. Assuming they were responsive I'd have given them the 10 days to confirm it was an actual issue, but I'd have expected them to notify the pubic and their users of the issue and mitigation steps within a week.

> users should be informed right away so that they can take steps necessary to secure themselves

For the record, this could be accomplished by a trustworthy source announcing "there is a critical vulnerability in Zoom's macOS software and you should uninstall it immediately pending vendor response". Some researchers do this already -- Tavis Ormandy has, for example.

It's not a binary choice between no disclosure and releasing an unpatched PoC.

By the way, I'm not trying to argue that this researcher behaved unethically, just sharing another option. My usual take is that the researcher gets a lot of leeway for having to make a difficult decision and presumably trying their best to balance consequences, similarly to how a pilot trying to land an emergency plane has great discretion in how they do so.

Re: Vulnerability in the Mac Zoom client allows malicious websites to enable camera

#50
Why isn't zoom running fully in the web browser at this point? Meet does this, and as far as I can tell the quality is indistinguishable from Zoom. Can someone with a better understanding of the underlying protocols shed light on why Zoom continues to ship a separate desktop app?
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