Serious IIS Hole; Minor X Bug 477
EyesWideOpen writes "Microsoft announced Wednesday that there is a serious software flaw with its IIS web server. The 'vulnerability affects a function in the server software that allows Web administrators to change passwords for an Internet site.' A researcher with eEye Digital Security discovered the flaw in mid-April but it wasn't announced publicly because of an agreement with Microsoft. The Wired article is here and this appears to be the MS bulletin describing the vulnerability in detail." And several people reported this Register story on a way to DOS Mozilla users by trying to display ludicrously large fonts. Microsoft's time to patch a remote hole where the attacker can gain complete access to your computer: two months. Open Source's time to patch a much less serious bug where the attacker can merely crash your computer: three days.
Only affects HTR - a rarely used feature (Score:5, Informative)
Incorrect ! (Score:5, Informative)
and
Slackware is still safe... (Score:2, Informative)
Re:Serious Linux Flaw? (Score:5, Informative)
Just putting something like ulimit -m 200000 in your startx script should limit X's memory usage to 200meg.
ulmit can also set upper limits on available CPU time, core file size, etc. Bash has a builtin version, so do man bash and look for ulimit for more details.
Re:Crashing X-Windows (Score:3, Informative)
I personally think Mozilla should implement some short-term patch to prevent exploitation of this bug until it's patched in XFree, but as the register article says, the fault doesn't lie with them.
They already did. It's obviously a trivial fix - no fonts larger than 1,000 (or whatever). I'm suprised it took that long.
Re:I already view large fonts. (Score:4, Informative)
I've also found that the screen calibration thingy on the fonts preferences (select 'Other..' under 'Display Resolution') makes a big difference too.
This is _not_ a bug in mozilla (Score:4, Informative)
Checkout the bugzila item here [mozilla.org]
Also, this is _not_ a DOS attack. What it does is make X consume all available memory and swap. And it can be triggered remotely by running mozilla, and browsing a webpage with absurdly large fonts. But it is by no means a DOS attack, because no-one is actively attacking you, making you "Deny Service" to other users.
Clarity on te Moz / "Linux" bug (Score:2, Informative)
That Mozilla can made to induce this does make Mozilla a critical problem - a malicious page can cause any desktop to crash using it. That it is not the "cause" of the problem is only a matter of semantics.
And of course, the fix is already in, specifying that fonts are no larger than twice the display height.
Find your way to bugzilla via the Register [theregister.co.uk] ;)
for enlightenment
Re:What rubbish (Score:2, Informative)
Debian backports security patches to whatever version they provide; look at their apache 1.3.9, it obviously doesn't have all the security bugs fixed up to the latest build..
Re:Crashing X-Windows (Score:2, Informative)
For someone who was brave enough to try the crashing link supplied by the Register, does this kill the whole machine, or just X? And can you salvage things without rebooting by using either a virtual term or logging in via ssh?
Yes, linux doesn't crash :-) You can still access through telnet/ssh. You can't switch to a virtual terminal, though.
Re:Status Quo (Score:4, Informative)
Ctl-Alt-Backspace if you get hit with it, and reboot your X-server. If you want a bit more protection, run XFS font server separately (rather than letting X handle fonts) then only the font server will crash.
As for "time to fix", well XFree86 has been out for a while now, so presumably it was vulnerable all along.
Re:Flawed logic (Score:2, Informative)
read the report (Score:1, Informative)
can a scruffly beard be far behind? will it help with the BiG ?pr? poosh?
Re:Crashing X-Windows (Score:2, Informative)
Since we all have "virtual memory" nowadays, it is entirely possible that a malloc() call reserves pages of memory that are only physically allocated once you use them. Whether or not this happens depends on your kernel's memory manager.
The IIS bug is _not_ that bad (Score:2, Informative)
MS actually _overplays_ this one in the release. For once. Too bad they claim its newly discovered.
OTOH the moz bug is (a) not in mozilla but in X as mentioned elsewhere, (b) not really fixed, just workarounded in mozilla and (c) A TOTALLY DIFFERENT ISSUE.
OTOH the IIS bug was an overrun and would be a 5min patch.
Re:Flawed logic (Score:4, Informative)
And while some (unsure about the percentage) mozilla fixes cause regression, they often hit the nail on the head with the first patch. In that ideal case the bug is squished within 3 days. Even if your "schedule" for mozilla fixes were correct, the mozilla developpers can do four iterations of that in the six weeks time it takes MS to issue their first patch. Then you assume that usually MS get's the fix right the first time, but if they don't and find regression after one week of internal testing they have to iterate too until they get it right and it'd be about as fast as an iteration in the mozilla case. If they catch it in the first week of "customer testing" they need 3.5 weeks for a cycle.
The advantage of the mozilla strategy is, that as soon as the patch is ready, anyone can test it (and at least the big linux distributions probably do so), and if there is a problem with a patch, information gets back to the developpers much earlier.
Re:Status Quo (Score:2, Informative)
Depends on the OEM (Score:4, Informative)
As for the HTR, anybody that does a "typical" install (i.e. just selecting default options) of a Web server has larger problems than their OS.
Re:Status Quo (Score:1, Informative)
And you're implying that IIS has only been available since mid-April?
The "time to fix" is the time from when the vendor is notified until they produce a patch.
Re:New MSN.com homepage code (Score:1, Informative)
*takes a look at his HTTP_USER_AGENT*
Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;
Re:Three days? Rather a bit longer.... (Score:4, Informative)
There's a huge difference (Score:3, Informative)
The X bug only crashes your machine if you browse to a malicious web site. The malicious person can't do anything to your machine if they can't induce you to go to their web site, and the effect on your machine of visiting the web site is immediately obvious (X and possibly your whole box crashes) so you can learn not to visit that web site again. The malicious user doesn't really gain anything other than the jollies of knowing they crashed some machine.
A remote access bug allows someone to take over your machine surreptitiously, which is much, much worse than just crashing your machine. It means your machine's data can be inspected and changed without your knowledge, and also that your machine can be used as a staging point for other illegal activities. Particularly if your data is sensitive, this provides a great deal more incentive to a malicious user.
The Font That Ate Cleveland (Score:3, Informative)
send the 'A' glyph, along with whatever hinting it needs for 'insanely, off the scale big' (i.e. probably the hint for the biggest glyph it defines, like 72 pt). The renderer takes the 'A' and converts it into a series of strokes. The strokes are then rendered into the clipped region, resulting in pretty instantaneous drawing. The font manager decides wisely that this rendered glyph, being "pretty big", shouldn't get cached as a bitmap the next time you want to draw it.
Here's how X does it:
Request the font for the 'A' glyph, scaled to 500 feet tall. Construct an uncompressed 1bpp bitmap of the letter A to give to X to blindly blit onto the screen. Die a miserable thrashing death.