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OS X sudoers exploit found in the wild

blog.malwarebytes.org

41–50 of 193 posts

Re: OS X sudoers exploit found in the wild

#41
post #3

I keep asking this question and Mac people keep looking at me like I'm an alien, so I guess I'll turn to the HN community for this questions. What do you recommend as security software for OSX currently? How do you help secure your devices from public wifi and the internet in general? Especially for novice users?

for preventive and (post)forensic measures see https://objective-see.com/

Re: OS X sudoers exploit found in the wild

#42
post #3

I keep asking this question and Mac people keep looking at me like I'm an alien, so I guess I'll turn to the HN community for this questions. What do you recommend as security software for OSX currently? How do you help secure your devices from public wifi and the internet in general? Especially for novice users?

Remove/Do not install Flash and Java, and make sure that Gatekeeper is at the middle setting. Turn your Firewall on regardless, and/or monitor your network activity. If you know what a packet is, then Little Snitch, if you don't Radio Silence is what I set my parents up with.

Re: OS X sudoers exploit found in the wild

#43
post #38
post #16

Earlier quoted context omitted.

I know that. Overwhelmingly in most cases it does help though, probably more than anything else short of air gapping the thing.

You can also install another OS. Putting an Ubuntu LTS or Debian stable on it will help you way more, compared to OS X 10.9.5, than any number of other mitigation strategies. Frankly, I'm way more comfortable taking my Windows 8.1 machine to public wifi hotspots these days than my OS X 10.9 machine.

... Unless you use Firefox.

Re: OS X sudoers exploit found in the wild

#44
post #3

I keep asking this question and Mac people keep looking at me like I'm an alien, so I guess I'll turn to the HN community for this questions. What do you recommend as security software for OSX currently? How do you help secure your devices from public wifi and the internet in general? Especially for novice users?

Security software is a band-aid on vulnerable software and users installing things they shouldn't. Part of the OSX security strategy is to minimize users installing things they shouldn't by making it difficult (enforced code signing, confirmations when opening an unsigned or new application). The other side is minimizing attack surface for exploits by staying up-to-date, not shipping crap like Java unless the user ex…

I believe in defense in depth. There is always going to be an escape. Within the last month there has been several different privilege escalations possible in OSX. While I appreciate OSX having a strong security model, secondary solutions are desirable too me.

Re: OS X sudoers exploit found in the wild

#45
post #40

I'm seriously shocked. This is ridiculous. This looks like possibly the easiest root exploit ever discovered on a desktop OS (a one-liner in bash). Why in the world would they allow an env variable to write to a file in a setuid'd binary? I'm suddenly very glad I don't use my macbook as my main machine, but I guess I'll remove the set{u,g}id bits on newgrp for now. Don't know if that will break things, but it's bette…

> This looks like possibly the easiest root exploit ever discovered on a desktop OS

Well there's always the classic "login -froot" bug [1]. Although, to be fair, you did say "desktop OS" and I'm not sure AIX exactly qualifies.

[1] http://seclab.cs.ucdavis.edu/projects/testing/vulner/18.html

Re: OS X sudoers exploit found in the wild

#46

Earlier quoted context omitted.

How can you be mad at Esser? He didn't put the bug there. He has nothing to do with this.

You forget your key when leaving for work, and don't lock your door. It was accidental, you have a lot on your plate. Your neighbour sees you didn't lock it, and tweets out, "Hey Mike at 321 Greyhat Bvld, you didn't lock your front door". He didn't send that to you as a text, he tweeted it. You come home, and you've been cleaned out. I'm sure we can all agree, you should have locked your door. Why be mad at your neig…

A better analogy would be your doorman, whose one job is to watch who gets into your building, leaving the key cabinet unlocked and going to lunch.

I don't mean to blame any individual human here, but I'm baffled at the process by which debugging environment variables were added to dyld without being carefully vetted for bad interactions with setuid binaries. This is a well-known easy place to screw up, and I'm surprised that someone was working on dyld without knowing that (although yes, humans forget things sometimes), and much more surprised that this made it past code review and into a shipping product.

This isn't a random screw up in regular software. dyld is security-sensitive; it's one of the small number of libraries that bears a responsibility to be paranoid about setuid.

Re: OS X sudoers exploit found in the wild

#48
post #20

Oh man, I really want to do it on all the macs at the Apple store, and start a little botnet. Problem is, I don't really have any use for 10 or so rooted macs. I mean, I could rm them, but I'd never do that, that's mean. And I wouldn't feel good about using the camera, even though the computers are in public, it's icky. Perhaps a DoS? There's nobody that I dislike enough for that. I think I'd be so rich if I wasn't s…

There's a reason that the store staff are instructed to encourage you to leave the store if you open a terminal.

Re: OS X sudoers exploit found in the wild

#49
post #43
post #38

Earlier quoted context omitted.

You can also install another OS. Putting an Ubuntu LTS or Debian stable on it will help you way more, compared to OS X 10.9.5, than any number of other mitigation strategies. Frankly, I'm way more comfortable taking my Windows 8.1 machine to public wifi hotspots these days than my OS X 10.9 machine.

... Unless you use Firefox.

Oh, yes, obviously use google-chrome (not even chromium; there's too much free-software-purity stuff in the Debian builds to make me feel comfortable with its security profile). At this point it didn't even occur to me you could use another browser and consider yourself secure, such is the awful world we live in.

Re: OS X sudoers exploit found in the wild

#50

Earlier quoted context omitted.

How can you be mad at Esser? He didn't put the bug there. He has nothing to do with this.

You forget your key when leaving for work, and don't lock your door. It was accidental, you have a lot on your plate. Your neighbour sees you didn't lock it, and tweets out, "Hey Mike at 321 Greyhat Bvld, you didn't lock your front door". He didn't send that to you as a text, he tweeted it. You come home, and you've been cleaned out. I'm sure we can all agree, you should have locked your door. Why be mad at your neig…

That's kind-of a bad analogy. It'd be better of:

1) The person who left the house open was certain to get the message quicker because of the tweet than just a text. 2) It was possible to quickly and remotely lock the door. Apple can and should fix this bug very quickly, as that is certainly possible for them.

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