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New Remote Root in Mac OS X

Cysgod writes "I've released a security advisory detailing a new remote root vulnerability in Mac OS X 10.3, 10.2 and possibly earlier versions." The main thrust is that it exploits a problem in the DHCP client, to gain root access, and turning off various services can prevent attack. It is unclear why an exploit was made public before Apple resolved the problem. Apple's fix is apparently scheduled for a December release.

19 of 445 comments (clear)

  1. Call me an Apple Apologist, but.. by grub · · Score: 5, Insightful


    OK, there's a hole. Still, when Apple (or OpenBSD) have a security hole it's newsworthy rather than just Business As Usual.. unlike other companies which promise security but can't deliver.

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    1. Re:Call me an Apple Apologist, but.. by FredFnord · · Score: 4, Insightful

      Most security holes aren't newsworthy. Remote root exploits, if they can actually be used, are, no matter what platform you're on. Thankfully, they're also rare, on most platforms.

      If someone can screw up your machine if they're sitting at it, or have an account on it, or are on the same (unswitched) subnet, that's annoying. If they can crash your machine remotely, or bring down its network stack, or DOS it to death with just one remote machine, that's really annoying. But when they can take it over, that's when it steps beyond annoying and becomes newsworthy.

      -fred

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    2. Re:Call me an Apple Apologist, but.. by HeghmoH · · Score: 4, Insightful

      Which category is it in if they can take over the machine, but only if they're on the same unswitched subnet, only if things are set up just so, and only if they're very lucky?

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  2. The Reason the exploit was made public.. by Smitty825 · · Score: 4, Insightful

    The exploit was made public before the official fix is that Apple had 48 days to fix the issue. Also, by releasing information about the exploit, Apple Sysadmins can make a minor change to their setup to prevent this exploit from occuring...

    Just because the exploit isn't public, doesn't mean that somebody else doesn't know!

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    1. Re:The Reason the exploit was made public.. by GigsVT · · Score: 5, Insightful

      I do agree that's plenty of time, but it's still questionable to release the exploit at this stage. He could have disclosed, and then if Apple downplayed it saying it wasn't exploitable, then released the exploit.

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    2. Re:The Reason the exploit was made public.. by TopShelf · · Score: 4, Insightful

      Why is this situation any different from new Windows exploits, which are shouted from the rooftops at the earliest opportunity?

      I'm not trolling here, just genuinely wondering...

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    3. Re:The Reason the exploit was made public.. by Greedo · · Score: 5, Insightful

      I have to say, I looked down that timeline as well and thought "Well, at least Apple is looking into the problem and has given a timeframe for an update (December)."

      Then, 5 days before December, they release the advisory.

      I don't think it's unreasonable for Apple to take some time confirming the exploit, and planning an update. Remember when they released an update that broke things?

      I *do* think it's unreasonable for Carrel to demand deadlines to Apple ... or anyone, really ... to fix their stuff. Especially when Carrel knows it's going to be fixed. Not much better than blackmail, if you ask me.

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    4. Re:The Reason the exploit was made public.. by ZxCv · · Score: 4, Insightful

      I don't think it's unreasonable for Apple to take some time confirming the exploit, and planning an update. Remember when they released an update that broke things?

      This exploit would take any qualified engineer at Apple less than a day to confirm, and it is serious enough that it shouldn't have to wait for a 10.x.z update to be fixed (and, in fact, 10.3 and 10.3.1, as well as in independent security update have all been released since Apple was notified of this issue). Any way that the entire system can be compromised remotely should be fixed immediately. Apple has released a few security updates that were completely independent of a whole system update, and they should have done exactly that in this case.

      I love OS X, but this is completely unacceptable. I'm just glad my Macs don't use dhcp.

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  3. Damn by JHromadka · · Score: 5, Insightful

    It seems pretty irresponsible to release details on an exploit when the vendor has already acknowledged the issue and has a date planned on when to release the fix. Now if Apple was ignoring them, that would have been a different story.

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  4. Nothing is infallible by Coryoth · · Score: 4, Insightful

    So, we have yet another security hole. No surprises there - they will come up eventually. It sounds as if the patching is reasonably prompt (though next month doesn't sounds that fast - hopefully that means it is well tested and it won't break anything like MS patches can). Ultimately though, we don't see many holes for MacOS X. Yes, I'm sure they exist, but they are a lot less frequent than some.

    For instance, there's still this unpatched hole in IE that MS doesn't seem inclined to do much about right now. So much for their "on average a patch in 24 hours" policy they were claiming. Looks like they'll get their patch out around the same time Apple does. I guess we hope that means that they've tested it this time...

    Jedidiah

  5. What is the fix? by stefanb · · Score: 4, Insightful
    I'm not sure I fully understand the problem, but it appears to me that the defaults of just accepting information from DHCP for authentication and authorization are wong; not necessarily any piece of software. (It is debateble whether the very possibility of obtaining such information from DHCP is such a bad idea that the option should not be offered at all.)

    Obviously, the fix is not quite so easy: instead of just updating a binary or two, Apple needs to devise a program/an advisory that will alert users to the problem, and that also makes sure people don't shoot themselves in the foot (turn option off, suddently you can't log in anymore).

    Devising such a thing, and testing it in a wide variety of environments will take time, so I wouldn't blame Apple for "reacting slowly" just yet.

  6. Re:Making rounds by Kunta+Kinte · · Score: 4, Insightful
    Apparently, it took 48 days from the time he informed Apple until now. Looks like he was itching to post something.

    I'd hardly consider waiting 48 days 'itching'.

    Sounds very responsible in my opinion.

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  7. Re:What does this mean to the average home user? by TheCrazyFinn · · Score: 4, Insightful

    Neither are vulnerable.

    The real worry is folks with an Airport card wandering around with their powerbook.

    The Exploit only works from the same subnet (As it relies on DHCP)

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  8. Re:Good News? by Jesrad · · Score: 4, Insightful

    Root account is disabled by default. Apple has chosen to make the users do all administrative tasks via sudo instead, which makes sense in the case of your clueless friends.

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  9. Re:Local insecurity by Commykilla · · Score: 5, Insightful

    If you have physical access to a machine, security is compromised anyway. You can rip out the hard drive and take/modify the bits by force if you want. If the machine is locked in a box, then you can't reboot it without being root, so the exploit doesn't work and you're still safe.

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  10. Background info by krisbrowne42 · · Score: 5, Insightful

    This is hardly a vulnerability, it's an ease of access feature that NeXT people have known about for almost a decade. The idea of this is, you take a computer out of the box, put it on your network, and it's working. Everything configured, users setup, etc. That should probably be shipped off by default, but I can understand the way they've done it in the past. It should also be noted that unless you've got a OS X server floating around, physical access to the network and management access to the existing DHCP server, this would be awefully hard to exploit.

  11. Show-boating, grand-standing by macdaddy · · Score: 5, Insightful
    IMHO this guy is show-boating. It is not unreasonable for an operating system company to take a non-critical but serious bug and spend 1.5 months developing and testing a fix. How many times have we seen a vendor rush to fix something only to seriously break things by not testing the fix thoroughly? Do we really want them to break something else? This isn't a minor piece of software like an FTP server where a security hole can be fixed in a morning, tested in an afternoon, and release the next day. I contend that even a piece of software as complex as Sendmail can be fixed and tested in a small amount of time and is really a minor piece of the puzzle when you're talking about an entire operating system.

    This exploit means nothing to very little the average user simply because no remote services are enabled by default. I'm using a 10.2.8 box right this minute and I had to enable Remote Login and Personal File Sharing.

    I really don't know where to start talking when it comes to the idiocy of releasing an exploit, not just a proof of concept, prior to the vendor releasing a fix. Apple wasn't dragging their heels. The whole timeframe is under 1.5 months. It is certainly not unreasonable to expect their programmers to spend time working on a bug fix. Hell the development cycle alone is more than a month if not two. So they didn't make the November 3 date. That's less than a month from the date the bug was reported. That's no surprise. I'd hate to rush a fix out that fast too. So the 10.3 Security Update and 10.3.1 Security Updates didn't fix it. Does he not realize that they were in the pipeline for testing back at the beginning of October? They aren't going to insert another code change in the middle of testing.

    IMHO this guy is show-boating, grand-standing, and showing that he has unreasonable expectations. The security vulnerability isn't that great. It's a hole, yes. It's not nearly as serious as a security hole in IE in which ALL IE installations are affected by "default." I think this guy should seriously be flogged for releasing an exploit at the same time as the advisory. That's just plain ridiculous. IMHO that alone speaks wonders about this guy. It's idiotic acts like this that seriously make me wonder about full disclosure. Anyhow, I've said my piece. Move along.

  12. Re:i thought i would never say this by JeffTL · · Score: 5, Insightful

    Well, actually, on most Windows boxen, EVERYONE is root.

  13. Re:What does this mean to the average home user? by EverLurking · · Score: 5, Insightful

    The theoretical risk if you use alot of public or unknown WAP's and can't account for how responsible/evil the owner of the WAP might be (who knows what nefarious acts those public WAP operators providing free broadband are up to...yeah, unlikely) is high as they could get root access and mount a directory with a new crontab that will start up a remote SSH daemon to access your computer with later. Hard to think someone would go through the trouble but you never know nowadays. Apple should have had a fix for this sooner or at least issued a Knowledgebase article.

    The fix is rudimentary, just go into your /Applications/Utilities folder, fire up the "Directory Access", uncheck a couple of boxes (the LDAP and NetInfo services)and you're done. Takes like 10 seconds to do, no reboot required, no other reconfiguration, no problems (under WinBlows, would have taken like 30 minutes of fruitless hunting around and a couple of reboots/patches and reconfiguration afterwards probably). Well, it would have taken 10 seconds if I hadn't already had these two services unchecked b/c some at www.OSXHints.com suggested that disabling unused directory services sped up your startup a little bit.

    If you need configuration information from a LDAP or NetInfo server (ie. at work), you could always create a new Location under your Network system preferences panel and go back to Directory Access, disable the relevant LDAP and NetInfo services on all your other locations except your work location. If you can't trust your work not to try to hack your computer with this exploit, you've got bigger fish to fry.

    For most home/SOHO users who are behind their own home router/firewalls and have otherwise trustworthy family members/roomates/co-inhibitants, this is a non issue (then again, if the people who live with you are trying to hack you are living with you, you have another far greater problems to deal with than this exploit : ). People on a shared subnet (like Cable Modem users) at risk if you're not behind a local/home hardware router/gateway device and someone else on your subnet wants to play "Hack the neighbor's Mac" with this exploit. I think you should be able to trust the DHCP information being handed to you by your DSL provider (again, if you can't then your problems go WAAAAAY beyond this exploit), no big deal. Correct me if I'm wrong but, I'm pretty sure my off the shelf LinkSys router doesn't know what to do with LDAP or NetInfo configuration info handed down by my ISP even if they did hand out any, and it certainly isn't set to pass it through to my internal subnet.

    But then again, what are you thinking NOT being behind at least a inexpensive (they're what, like under $100 now even with 802.11g?) NAT/SPI firewall that's up and running 24/7 regardless of how your computer is configured if you're on Cable Modem or DSL at home?

    In short, a easy fix and not really a problem for most home/SOHO users. You can breath easy now.

    DaveC

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