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Alarm Raised For "Clickjacking" Browser Exploit
Posted by
timothy
on Thu Sep 25, 2008 03:19 PM
Shipment Date writes "ZDNet's Zero Day blog has some new information on what looks like a scary new browser exploit/threat affecting all the major desktop platforms — Microsoft Internet Explorer, Mozilla Firefox, Apple Safari, Opera and Adobe Flash. The threat, called Clickjacking, was to be discussed at the OWASP conference but was nixed at the last minute at hte request of affected vendors. From the article: 'In a nutshell, it's when you visit a malicious website and the attacker is able to take control of the links that your browser visits. The problem affects all of the different browsers except something like lynx. The issue has nothing to do with JavaScript so turning JavaScript off in your browser will not help you.'"
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Submission: Alarm Raised for 'Clickjacking' Browser Exploit by Anonymous Coward
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Fixes Released (and More Promised) For "Clickjacking" Exploits 70 comments
An anonymous reader writes "As discussed previously on Slashdot, concern has been raised over a class of 'clickjacking' vulnerabilities which affect all major Web browsers. These exploits allow an attacker to place invisible or seemingly legit objects on a Web page that perform undesired actions when a user clicks on them. In recent developments, 'Guya' posted a scary proof-of-concept that hijacks Adobe Flash Player to spy on users with a webcam and/or microphone. In response, Adobe released an advisory with a temporary workaround, and stated that a future Player update will address the exploit. This prompted the original disclosers of the vulnerabilities to post a summary of the exploits. Additionally, Giorgio Maone, creator of the popular NoScript extension for Firefox and other Gecko-based browsers, released version 1.8.2.1 of NoScript, which adds 'ClearClick,' a feature that intercepts clicks made on invisible or otherwise obscured elements on a page. Although issues remain, there seems to be progress in addressing these security problems."
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Hurray for us lynx users! (Score:5, Funny)
*crickets*
Re:Hurray for us lynx users! (Score:5, Informative)
Hmm, I'm able to use lynx to log into Gmail. Granted, I had to accept a million cookies and other things along the way.
Lynx Version 2.8.6rel.4 (15 Nov 2006)
libwww-FM 2.14, SSL-MM 1.4.1, GNUTLS 1.6.2, ncurses 5.6.20080308(wide)
Built on linux-gnu May 2 2007 08:54:50
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Re:Hurray for us lynx users! (Score:4, Informative)
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Re:Hurray for us lynx users! (Score:5, Informative)
I didn't RTFA, so I don't know how appropriate this term is.
Don't worry, you didn't miss anything. The article basically says, "OMG WE ARE ALL SO PWNED!!111. But we're not going to tell you why."
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Re:Hurray for us lynx users! (Score:5, Funny)
Or Holdingdownholdingdownholdingdowncrapupupupenter-jacked.
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The first thing I thought of (Score:4, Funny)
Re: (Score:3, Funny)
"The first thing I thought of was some weird mouse-mastubation scenario."
"Mastubation"?? I'm picturing small rodents with catheters....
Even my capybara Lemmiwinks thinks THAT is sick.
Information (Score:5, Insightful)
Re:Information (Score:5, Funny)
It's very similar to the DNS issue from a couple of months back: It's a hugely scary thing that will doom the Internet, but because we're responsible we can't tell you what it is in any detail. However, if you don't patch your browser immediately (patch not yet available), you are fucked.
Have a nice day.
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Re:Information (Score:5, Funny)
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Re:Information (Score:5, Insightful)
There's a big difference. The first public news of the Kaminsky DNS issue was with the release of Microsoft's Patch Tuesday DNS update, with simultaneous patches from ISC for BIND and the other affects nameservers. Dan organised all that with the help of CERT and the DNS server vendor/distributors, without leaks. Once the patches and a vague description was out, people put two and two together pretty quickly - IIRC from the BlackHat preso, the first correct solution Kaminsky received was within 48 hours - and shrewd guesses were being made within two weeks (followed by the unfortunate leak which broadly confirmed the guess.) It sounds like the cat is well and truly out of the bag here, already, and there are no patches yet. Apart from the people at the conference, there's enough detail in the sources the ZDNet blog links to to make it pretty clear which direction the shrewd guesses (and testing) will have started on.
Looking on the bright side, more browsers than nameservers auto-update themselves...
(Incidentally the reason the Internet wasn't destroyed by the Kaminsky bug was precisely because of all the prior coordination and then unequivocal "patch now" messages from multiple credible sources (CERT, Vixie, Microsoft, the other respected researchers Dan explained it to under NDA, etc.) And anyway you ARE still fucked in the long run, anyway, because DNS is still spoofable by a determined attacker (which probably means one who's going after a very high value target) in the absence of DNSSEC. Hence the (by Fed terms, frantic) haste with which the .gov root is being signed at last.
Have a great day!
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Re:Information (Score:5, Informative)
It's about using IFRAMES + CSS to make confusing visual elements that cause users to perform actions they didn't think they were performing. Feel better? ;-)
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Re:Information (Score:5, Funny)
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Re:Information (Score:5, Funny)
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Re:Information (Score:5, Insightful)
Sure. Imagine you're in a car showroom looking at a super-expensive car. It looks great and price is pretty good. So you tell the dealer you'll take the car. Except when you get in the car, you realize that someone had put a cardboard cutout in front of the car. The car you got in was actually an economy vehicle. Except now it's too late to undo your purchase!
Here's another one: Let's say you've got a bunch of buttons on your dash. Most of them control the radio, but one controls the ejection seat. While you're away, some neighbor kids from MIT think it's funny to come over and rewire the buttons on your radio. Now when you press the button to turn on your radio, you actually get ejected from the car. NOT FUNNY!
Better? :-P
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Re:Information (Score:5, Funny)
Better? :-P
Well, That's better than simply turning on the radio when you needed to eject.
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Never gonna... (Score:5, Funny)
Re: (Score:3, Funny)
With all the horrible things on the Internet, you're worried about rickrolls? Have some priorities.
We're all going to end up seeing goatse.cx again.
Re:Never gonna... (Score:5, Funny)
We're all going to end up seeing goatse.cx again.
yeah but now it will have Rick Astley playing in the background...
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Summary wrong (Score:5, Informative)
The issue has nothing to do with JavaScript so turning JavaScript off in your browser will not help you.'
The quote from the article says you can protect yourself by disabling scripting:
In the meantime, the only fix is to disable browser scripting and plugins. We realize this doesnâ(TM)t give people much technical detail to go on, but itâ(TM)s the best we can do right now.
Re:Summary wrong (Score:5, Informative)
The first quote is also from the article, so it's not the summary's fault. The article is vague and self-contradictory, so I'm calling bullshit until and unless further details are given.
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Re:Summary wrong (Score:5, Informative)
The zdnet article is pretty vague, but I think it refers to the problem detailed in this message from Michal Zalewski [whatwg.org]:
"A malicious page in domain A may create an IFRAME pointing to an application in domain B, to which the user is currently authenticated with cookies. The top-level page may then cover portions of the IFRAME with other visual elements to seamlessly hide everything but a single UI button in domain B, such as 'delete all items', 'click to add Bob as a friend', etc. It may then provide own, misleading UI that implies that the button serves a different purpose and is a part of site A, inviting the user to click it."
Disabling JavaScript won't prevent the attack. It will break some mitigations, though!
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Re:Summary wrong (Score:5, Interesting)
FWIW, this isn't exactly a new idea. roc and I discussed it back in 2002 [mozilla.org].
I'm glad it's getting attention now, though. Any fix is likely to require changes to specs.
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Re:Summary wrong (Score:4, Insightful)
That's true, but the big problem is that the debit card money comes out of your account immediately.... even if you do get it all back, there is the possibility for this to happen:
1- you check your bank balance in the morning
2- you make a string of purchases, knowing that you're safe in your balance
hidden step 1.5 - someone illegitimately uses your bank card and zeros you out.
hidden step 3 - every purchase you made hits you for a $20-40 overdraft charge, which you may or may not get back, and even if you do get it back, it takes a finite amount of time, during which every other transaction that may not have posted yet ALSO hits you for overdraft, and you can't use your card, and have no money.
It's a really awkward and annoying situation to be in, for sure.
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Re:Summary wrong (Score:5, Informative)
+1 for "vague and self-contradictory."
From TFA: "The issue has nothing to do with JavaScript so turning JavaScript off in your browser will not help you." and then "The exploit requires DHTML." As far as I know, DHTML requires a client-side scripting language--the most popular of which (only?) is JavaScript.
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Re:Summary wrong (Score:5, Informative)
the problem is actually in dhtml, but javascript makes the exploit 'much easier'
hence, the attack sites will all be using javascript, because it's easier than writing it entirely in dhtml just to score and extra 1 click from the guy who disabled javascript because he doesn't trust it.
BTW: in theory even sites like slashdot can be infected because the attack applies to all CSS coded sites. nice.
oh, BTW, is you have noscript installed, this vulnerability can only force clicks within the same domain, since cross site code is automatically disabled.. AFAIK the only way to disable CSS is to use obsolete browses like lynx.
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Re:Summary wrong (Score:4, Informative)
I thought "DHTML" was just a term for manipulating the DOM on the fly using JavaScript. How do you do DHTML without JavaScript?
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Re:Summary wrong (Score:5, Insightful)
Try the CSS pseudoclass :active to move things around, like make a facade image positioned to cover a real button disappear with display: none;.
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Re:Summary wrong (Score:5, Insightful)
Try the CSS pseudoclass :active
And here is an example [bonrouge.com].
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Thank Jeebus! (Score:5, Funny)
Re:Thank Jeebus! (Score:5, Funny)
Finally I have a legitimate excuse for all the pr0n sites that are in my browser history. No honey, it isn't me, it's a browsers exploit! I swear!
I don't know how things work for you, but saying that I just got clickjacked is only going to get me into more trouble, not less.
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Bullshit? (Score:5, Insightful)
I don't think this exploit really exists. A cross browser cross platform exploit that doesn't use javascript?
Won't be losing any sleep over this one.
Re:Bullshit? (Score:5, Insightful)
Except you're wrong, but don't take my word for it (I run ha.ckers.org with RSnake), see what Adobe has to say.
http://blogs.adobe.com/psirt/2008/09/thanks_to_jeremiah_grossman_an.html [adobe.com]
-id
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Premature claim (Score:5, Interesting)
I didn't find that information in TFA or in any of the TFAs linked in TFA (here [adobe.com] here [ckers.org] here [blogspot.com] here [webadminblog.com]). Though it may be so; it sounds like this exploit makes use of the browser's access to the clipboard.
Elinks FTW!
OWASP (Score:5, Interesting)
Well, add OWASP to the list of security organizations with no integrity. It's clear they care about their sponsors, not their members.
didn't click (Score:4, Funny)
One of these things is not like the other. (Score:5, Insightful)
Web browser, Web browser, Web browser, Web browser, and cross-platform method for running code delivered from untrusted sources.
From TFA:
One vendor is, unlike the others, mentioned by name. It happens to be the vendor that ships The One Thing That Is Not Like The Others.
Also from TFA:
and
"In the meantime, the only fix is to disable browser scripting and plugins. We realize this doesn't give people much technical detail to go on, but itâ(TM)s the best we can do right now."
Now we're at a quandary. Your humble correspondent is at a loss to even speculate as to the nature of a technology that Ffirstly isn't Javashit, but which can conceivably be invoked by web content regardless of which web browser is in use, but lastly can be secured against by disabling hated plug-ins.
Re:One of these things is not like the other. (Score:5, Interesting)
> Now we're at a quandary. Your humble
> correspondent is at a loss to even speculate as
> to the nature of a technology that Ffirstly isn't
> Javashit, but which can conceivably be invoked by
> web content regardless of which web browser is in
> use, but lastly can be secured against by
> disabling hated plug-ins.
It's a Flash exploit. I found a proof-of-concept by clicking around TFA, and it promised that the Flash movie would take over my clipboard, forcing me to close the browser window. I'm on Firefox 3.0.2, and the "proof-of-concept" did nothing.
At least nothing obvious. I suppose I could have been rootkitted.
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But does it affect the links browser? (Score:3, Interesting)
Using the links browser in a terminal with mouse support is almost exactly like using a browser with images turned off...
Witness:
http://www.jikos.cz/~mikulas/links/screenshots/png.html [jikos.cz]
Scary? (Score:5, Insightful)
I'm trying to think of the ways this could be used to cause harm, so far the biggest threat I see is to the pay-per-click ad model, since this would be great for clickfraud. Other than that, a website could bounce you to another page on their site that you didn't intend to go to, and possibly overwhelm your browser & bandwidth with a redirect loop. I can see a hint of an issue in the way frames might be used with this exploit and 3rd-party sites (as noted in the article), but that seems to be a bit of a stretch since the original site would still be sending someone away from their site in another redirect. Plenty of sites who make the choice to be annoying already make you go through a little effort to break out of their frames when you go to an external site from one of their links, it's not the end of the world.
I'd like to hear other folks' ideas on ways this may be used for an exploit that could do damage to anything other than Google's bottom-line. Until I hear a more compelling one, this exploit doesn't strike me as being the least bit "scary". A "small potential nuisance" might be a more apt description, since it would be fairly simple for end users to just ignore its effects.
zomg Flash is insecure (Score:3, Funny)
I've seen this as a bug (Score:5, Interesting)
I've seen situations that otherwise look like benign layout bugs, where two or more hyperlinks or other clickable objects end up being overlayed on each other. It's not clear which one would be activated until you click. If someone intentionally did this AND obscured the object they wanted the victim to click, and made the other object more attractive, people might be doing such clicking. This could be easily done with CSS on one page, but there's not advantage since both links are just part of the same page. I don't think frames would do this. However, IFRAMES might do this on a cross "page" basis. The perp makes an attractive link that overlays over an iframe that is loaded from another page, so the act of clicking gets the victim to effective click on the other page. This loads something else in the iframe, but from the perpective of that other web site, it was a click on their page (based on the referer value). The simple exploit would get people to click on an ad, and it would not be visible to the ad vendor which page was doing the exploit.
My take (Score:5, Informative)
From google cache:
Clickjacking
Thereâ(TM)s been a bit of drama over the last week or so around the upcoming world OWASP conference in New York. Itâ(TM)s surrounding a talk that Jeremiah and I were planning on doing the first day of the conference. Jeremiah and I have been working on some interesting browser security issues which also effect a lot of downstream people/websites/technologies as well. Sounds like a good talk right? We thought so too!
Alas, it turns out that some of the issues we found werenâ(TM)t just a little bad - they were a lot bad. So bad, in fact, that we felt compelled to do some responsible disclosure. One issue lead into another issue into another and poof - we have at least two and probably more incoming vendor patches at a yet to-be-determined date. And weâ(TM)ve only worked with a few vendors. So⦠yah. Itâ(TM)s pretty bad.
As you may have guessed the first is a browser company, Microsoft (to be expected since itâ(TM)s a browser issue to begin with). The second is Adobe - who have been working closely with us on this one since we first told them about the problem. We have been working on proof of concept code since before Blackhat and finally got our ducks in a row with real working exploit code a few weeks ago. And that is pretty much when the problems started. None of the issues we found relating to the browser were particularly easy to fix, it turns out.
The related issues we found that affect websites (instead of browsers) is thankfully slightly easier to deal with on a one off basis, but that too is going to be a problem. There are a lot of much easier hacks out there against websites for sure, but what weâ(TM)ve been working on breaks some previously good security measures. The correct solve will not be patching every web-site on earth. Instead it will likely end up being a browser patch against every major browser. The idea of every webmaster in the world patching their own sites is a non-starter. Although Iâ(TM)m sure lots of people are going to run out and patch their sites rather than wait for the normal browser patch and release cycle for all browsers everywhere. Weâ(TM)ve discussed the high level concern with both Microsoft and Mozilla and they concur independently that this is a tough problem with no easy solve in sight at the moment.
So, after much deliberation we opted to pull our speech voluntarily, due to the extremely neutered information weâ(TM)d have to be sharing. Weâ(TM)d much rather share the full breadth of what we found when it can be discussed more openly as to not diminish the danger of the flaw by only talking about small parts of the issue. There will still be holes in many websites due to this problem even after the short term patches are available, but weâ(TM)d rather a few of the more critical problems get patched before we go public.
However, I must stress, this is not an evil âoethe man is trying to keep us hackers downâ situation, a la Michael Lynn vs. Cisco, or Chris Paget vs. HID, or MIT vs. MBTA and so on. We proactively decided it was better to pull the speech ourselves for the time being and for anyone who was looking forward to the speech all I can say is I hope to make it up to you once the vendors are in a better spot. It wasnâ(TM)t an easy decision but it really feels like the best option we have given the current situation. If youâ(TM)re desperate for a way to patch your browser from the issue disable scripting and plugins for the time being. More to come.
This entry was posted on Monday, September 15th, 2008 at 5:36 pm and is filed under Webappsec. You can leave a response as well.
And from the Adobe report:
Thanks to Jeremiah Grossman and Robert "RSnake" Hansen
Robert âoeRSnakeâ Hansen and Jeremiah Grossman recently shared with us some information they were planning to include in an upcoming presentation at the OWASP NYC AppSec confer
The devil is in the details (Score:5, Informative)
In its most primitive form, it basically involves taking an iframe, figuring out where the link part/form part is, and then tricking the user into clicking it.
This seems very clunky and hacky, but I suspect that the speakers at the OWASP talk have gotten this technique to work well enough so that it is both transparent and highly effective. Can you think of a website that needs you to click, say, a play button in order to view content? That click may be hijacked through an invisible iframe to execute an action on another website.
The good folks at Google recently raised this topic on the WHATWG mailing list, you can read more about it here: http://lists.whatwg.org/pipermail/whatwg-whatwg.org/2008-September/016284.html [whatwg.org]
Re:Konqueror? (Score:5, Funny)
The summary clearly states that only lynx is not affected. It's pretty obvious what's going on here: the exploit is a nefarious plot to make everyone switch over to lynx, thereby crippling the non-text-based porn industry.
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Re:Konqueror? (Score:5, Funny)
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Re:Turn to Lynx? (Score:4, Informative)
Lynx and Links do not support IFrames, so they are not vulnerable. In fact, any browser not capable of advance CSS and/or IFrames is safe. Unfortunately, that's not very many browsers.
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Re:Turn to Lynx? (Score:5, Funny)
I hate to burst you bubble, but it does not mean I'm 12. It means that I'm older than sin [livinginternet.com].
You young'uns these days just don't understand anything that has a black rope coming out the back. It's got to be all "txtm3 or gtfo". 4COL. Well, @TEOTD I have a message for you, young man! GOML* and GAL! --AKAIB
* Get Off My Lawn
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Re: (Score:3, Insightful)
That's not it because the description says that disabling Javascript will not help. The bug indicated by you says disabling Javascript will help.
Re:Go Lynx! (Score:5, Insightful)
i wouldn't exactly call the ability to render images "frills." i can understand if this were 1990 and the web was still mostly text-based. but the idea of a hypertext network and hypertext documents is to go beyond what normal text documents/interfaces could provide.
lynx has its merits, but calling all standard browsers too complicated or excessive is stretching it a bit. if lynx were just a basic browser that didn't have plugins, tabs, adblock, RSS readers, bookmarks, search tools, etc. then you could claim that other browsers have too many frills.
but lynx is a text-only browser. that's like saying a radio is a TV without the frills. stripping out core features does not make something have a cleaner interface or mean that the removed features are unnecessary.
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