2 Firefox Security Flaws Lead to Exploit Potential 417
Marthisdil points out a News.com story which reports that "Two vulnerabilities in the popular Firefox browser have been rated "extremely critical" because exploit code is now available to take advantage of them." Security firm Secunia reported the vulnerabilities (and the "extremely critical" rating is theirs), but the News.com story points out that thus far, "no known cases have yet emerged where an attacker took advantage of the public exploit code." Update: 05/09 20:20 GMT by T : Rebron of the Mozilla Foundation sends a correction; this is really the same flaw reported yesterday. He suggests that you glance at the Mozilla security alert on this hole (as well other alerts at the Mozilla Security Center), and says "The Mozilla Foundation has made changes to our update servers that will protect users from this arbitrary code execution exploit."
Dupe... (Score:4, Informative)
Bug Details (Score:5, Informative)
Exploitation requires the javascript bug AND a whitelisted site. The only default whitelisted site is the update.mozilla.org, and they have made changes to mitigate the problem on their end.
So unless you've whitelisted a lot of extra sites to install themes or extensions, this is not a huge risk. To be sure, disable install "Allow websites to install software" under options | web features, and if really worried, disable javascript.
Apologists...Start your Engines (Score:0, Informative)
"But...IE...Disable Javascript....NOT FAIR!!"
Re:Bug Details (Score:5, Informative)
RTFA. The site that runs the exploit does not have to be on the site you whitelisted. Part of the exploit is that it can pretend to be a site you whitelisted. The other part is that it can sneak in some javascript code where it shouldn't be able to (an icon url).
Contrary to the grandparent post, it is not enough that mozilla has updated their site. That mitigates only part of the problem, and only if you haven't whitelisted other sites.
Until 1.0.4 comes out, disable javascript.
Re:See! See! (Score:5, Informative)
One report says as follows:
Because the foundation controls all sites in the default software installation white list, it has been able to take preventative action by placing more checks in the server-side Mozilla Update code and moving the update site to another domain.
The foundation said users who have not added any additional sites to their software installation white list are no longer at risk.
So one down, the other to be fixed shortly.
Re:And to think... (Score:1, Informative)
Except for the lack of ActiveX support.
Re:And to think... (Score:5, Informative)
Overall, I think Firefox is more secure than IE and will just grow to be increasingly more secure with time. That doesn't mean it is flawless.
One Vulnerability Already Fixed (Score:5, Informative)
Because the foundation controls all sites in the default software installation white list, it has been able to take preventative action by placing more checks in the server-side Mozilla Update code and moving the update site to another domain.
The foundation said users who have not added any additional sites to their software installation white list are no longer at risk.
So one down, the other to be fixed shortly.
Meanwhile I got a notice this morning that tomorrow's Microsoft security patch will fix one major flaw, but leave others unpatched UNTIL NEXT MONTH.
So much for "days of unpatched vulnerability" supposedly favoring Microsoft.
Re:And to think... (Score:4, Informative)
Re:And to think... (Score:1, Informative)
Re:Updating/Using only ONE copy of Firefox?? (Score:3, Informative)
Note that all of your extensions, bookmarks, themes etc are stored in one directory (on Windows, it's in %appdata%/firefox/, or something - I do't have access to a Windows machine right now) so you just need to carry this directory around with you - no need to manually install extensions etc every time you do a new install.
Re:And to think... (Score:3, Informative)
Three syllables: ActiveX [google.com]. If a "feature" is so bug infested that it's worse than useless, can you consider it a bug?
Re:Does this affect Mozilla also? (Score:3, Informative)
Re:sorry.. (Score:3, Informative)
I'd rather get a headsup here, or even better yet
Should not be exploitable any more (Score:5, Informative)
Re:And to think... (Score:2, Informative)
Solution (Score:5, Informative)
Re:sorry.. (Score:2, Informative)
Re:And to think... (Score:3, Informative)
Re:sorry.. (Score:5, Informative)
Re:sorry.. (Score:4, Informative)
Reposting the story ad nauseum won't make it any more interesting or useful.
Re:sorry.. (Score:5, Informative)
Firefox bugs get on the front page when they are exploitable in theory (this exploit here also worked only for a couple of hours because Mozilla's servers have been modified so Firefox is redirected to a non-whitelist site) while IE bugs get on the front page only when they cause serious mass infections.
The bugtraq post... (Score:5, Informative)
From BT:
Firefox Remote Compromise Technical Details
Before I start, I need to say that this thing has been patched on Mozilla's server. If you take a look at any of the extension install pages on their site, you will see that the install function has a bunch of random letters and numbers after it. Even though this would probably be an easy thing to bypass, I am not going to attempt it because of the uselessness of such a bypass. A patch is already in development and so any more work going into fine-tuning this exploit would be a waist of time.
There are three core vulnerabilities being used in my example. A friend of mine (Michael Krax, http://www.mikx.de/ [www.mikx.de] helped me with the research.
To understand why the example works, one must understand the basics of how Firefox works. Everything you see in firefox is essentially a webpage being rendered by a compiler. This is what the gui is made of, and this is why firefox is so easy to customize. However, it also allows for some security bugs. If one could get one of the chrome pages to request a javascript:[script] url, that individual would be given complete access to the system because chrome urls are given full rights in firefox. My example works by tricking the addon install function into displaying an icon with a javascript url.
However, this would not be enough to compromise the system. By default, the install feature only works when called from a page within update.mozilla.org or addon.mozilla.org. Therefore, another (cross site scripting) vulnerability had to be found to call the install feature from mozilla.org. This vulnerability navigates to a javascript page and displays a link (pointing to a mozilla.org page) within a frame that follows the user's cursor. After the user clicks, the link is navigated to, which fires the onload event. This is a buggy event in Firefox because with it we can now access certain parts of the window object that we shouldnt, such as the history object. After the page loads, we use the history object to navigate backwards to the javascript page. The javascript is executed again, now from update.mozilla.org because when we navigated backwards, we essentially navigated to a javascript:[script] page. Now we call the install addon feature, which displays a dialog with det
ails of the requested addon, including an image with a specified image. This image points to a javascript:[script] url, which gets executed in the context of chrome. Now we have compromised the system
Whew, that was quite a mouthful.
I am still trying to gather all the details as to how my research was leaked, but recent conversations are leading me to believe that it was a misplacement of trust, not a server compromise. However, I do not want to jump to conclusions too quickly, as this will only lead to more problems. That's all I will say about that subject, as I don't want to offend anybody.
Also, I would like to let everyone know that this is not the only vulnerability that Mikx and I have found. We still have a couple of tricks up our sleeves, and you can be sure that we will not make the same mistake twice.
If you want to see the original PoC, here is the url:
http://greyhatsecurity.org/vulntests/ffrc.htm [greyhatsecurity.org]
Paul
Greyhats Security
http://greyhatsecurity.org/ [greyhatsecurity.org]
Re:Bug Details (Score:4, Informative)
Just unmark Options -> Web Features -> Allow websites in to install software.
Re:And to think... (Score:3, Informative)
Thing is: ActiveX is "broken as designed", whereas alternatives may be "broken due to bugs": in latter case it can be fixed, and exploits are generally more limited in scop.e
Re:What Firefox needs is... (Score:1, Informative)
Re:sorry.. (Score:4, Informative)
Right back at you.
There's working exploit code in the comments to this very storyI guess you missed the part where Mozilla Foundation has corrected the problem on their servers, and given instructions to take any third party websites off the whitelist? The exploit code simply has no effect if that basic precaution is followed.
While the above mentioned fixes and workarounds aren't perfect, they do eliminate the problem for now. A more thorough comprehensive fix is under development.
This is no worse than that IE exploit that was redirecting people to that scammer site in Russia (forget the name of the exploit). MS issued a "fix" which didn't address the flaw in the software at all - they basically just added that one specific scammer site to the hosts-deny list (Yes I know that's not perfectly accurate, but it's basically what they did)
BTW, nobody here is impressed with your pottymouth language.
TommyRe:And to think... (Score:3, Informative)
Actually, most IE exploits are discovered by third party security firms, such as F-prot and Secunia. It's often months between the discovery of the flaw and a solution - you just weren't told there was a problem.
Black hat hackers also have debuggers. They can find IE exploits as easily as those third party security firms. It all comes down to who finds it first - white hat or black.
The ratio of white hat vs black hat hackers working on an app has a lot to do with how potentially insecure it is, and Firefox has many, many more whitehats than IE.
TommyRe:Mozilla's Security? (Score:3, Informative)
Except for the security problems, which they don't allow the public to see.
Re:And to think... (Score:1, Informative)
They killed it because the Longhorn team was including a ground up IE replacement. They did it ground up because IE couldn't get integrated tightly enough into the OS for the Longhorn folks comfort. Certainly gives me warm fuzzies over Longhorn, given that IE's problem all along has come from the OS integration.
Anyhoo, since Longhorn is a Microsoft OS project, it's long overdue - when it passed a year, and security exploits because such a PR problem that Microsoft implemented their once-a-month-patch schedule (there's that warm 'n fuzzy feeling again), they rounded up a team to start working on IE full time again. Of course they're working on IE7, other people still have their jobs maintaining IE6.
Trust me, Microsoft doesn't allow departments to go live in caves. The political infighting alone requires them to see daylight on a consistent basis, and Microsoft has managers, managers managing managers, managers managing them, etc. - all require frequent status updates and validation.
Think of Microsoft as the merger of Dilberts and Goldfingers companies and you're not far off from the average workday.
Re:Bug Details (Score:3, Informative)
Wrong. There are two parts to this exploit. Your solution covers one half. There is still an exploit where someone can get javascript to run as part of an icon that is loaded. The mozilla.org site itself states this:
"To prevent the script injection exploit from stealing cookies or other sensitive data disable Javascript before visiting untrustworthy sites."