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Public Exploit For Windows JPEG Bug

Posted by michael on from the here-comes-the-worm dept.

Khoo writes "A sample program hit the Internet on Wednesday, showing by example how malicious coders could compromise Windows computers by using a flaw in the handling of a widespread graphics format by Microsoft's software. Security professionals expect the release of the program to herald a new round of attacks by viruses and Trojan horses incorporating the code to circumvent security on Windows computers that have not been updated. The flaw, in the way Microsoft's software processes JPEG graphics, could allow a program to take control of a victim's computer when the user opens a JPEG file." We mentioned this earlier.

8 of 509 comments (clear)

  1. Patch is Already Out by darkmeridian · · Score: 5, Informative

    The patch for this one is already out. Furthermore, SP2 systems do not have this vulnerability unless Office is installed. SP2 by default has auto-updates enabled. And for Office to be exploited in a SP2 system, the user has to open the file manually.

    Code is always buggy. Even Firefox had a JPEG vulnerability of its own. This is dumb ownership, if this bug becomes prevalent.

    --
    A NYC lawyer blogs. http://www.chuangblog.com/
    1. Re:Patch is Already Out by maxwell+demon · · Score: 5, Informative

      Well, you know, that's called a software bug. A software bug is by definition something you didn't intend.

      Actually, it's a buffer overflow. A buffer overflow means that there is some area of memory reserved for some data, and then there's more data written to it than fits in. This causes some other data to be overwritten; if that other data happens to be a return address (basically a number which tells the computer where to continue after finishing the current task), then you can get the computer to execute arbitrary code which is in memory - including the code you just conveniently placed into the memory as "image data".

      I don't know details of the JPEG image format, but with a simple bitmap format, a buffer overflow might happen as follows:

      The image contains the number of pixels, and the bytes per pixel. The program takes those numbers, multiplies them, and reserves that much memory to take the pixel values. Then it reads the rest of the file as image data into that memory.

      Now, this simple program for this simple image format may be easily exploited: Just put more data into the image than the product of number of pixels and bytes per pixel. Then the program as written will not reserve enough memory for that data (because the values at the beginning don't tell the truth), and therefore the data will overwrite anything following the data.

      Ok, the fix is easy: Don't read more data than you allocated memory for. The problem is that on one hand, there are C standard functions which make it easy to get that wrong, and second, there can be more subtle ways to produce the same result. For example, the multiplication could overflow, resulting in too little memory being allocated, while the given number of pixels is read in (under the believe that you have reserved enough memory for that).

      And yes, buffer overflows happen in open source software as well as in Microsoft software.

      --
      The Tao of math: The numbers you can count are not the real numbers.
    2. Re:Patch is already out by BoldAC · · Score: 5, Informative

      Come on guys! This is slashdot!

      Where is the downloadable link to the second proof of concept code?

      Here's the link to the first POC:
      http://www.gulftech.org/?node=downloads

      The first POC just generates the buffer overflow crash. Interesting enough, on an unpatched system, just having the jpg on your desktop caused by explorer to crash - repeatedly. I am assuming as XP tried to generate the thumbnail. However, if viewed through a web page, I could view it fine.

      I've been looking for the second POC code since yesterday. It supposedly opens a cmd prompt when the crafted jpg is viewed.

      AC

    3. Re:Patch is already out by Trigun · · Score: 5, Informative

      http://www.k-otik.com/
      You can find it all there, including a C program that fires off a local cmd shell.

      Only for use as a security lesson and ethical hacking.

  2. Patch is already out by Jeffv323 · · Score: 5, Informative

    Pick your OS and download it here

    Also, if you have SP2 or uh, don't use MS software, you're fine :)

    --
    I'm a minister!
  3. patch has been available for a while now by jeffs72 · · Score: 5, Informative

    And it actually works fairly well. It scans for any program that reads these files and makes sure they don't have the bug in them. If it can't patch them, it bugs you about it so you can find a fix for the app. Only Microsoft apps of course, I don't think Adobe wants Microsoft pushing out software updates for them.

    Most of the users I have to support aren't savvy enough to add a printer (omg, with active directory it's like 3 mouse clicks) or install software or apply updates (we use some banking software and it notifies you with a text box to click "OK" and then "File, Update" but I still get called on it every time). That's why at our offices we use Microsoft System Update Server (SUS). It lets us approve patches and then roll them out to all the clients in the domain automagically.

    I shudder to think what would happen if I tried to roll out firefox or mozilla to everyone. I'd probably get calls that their "e" was missing and they couldn't connect to the internet. I swear, some people just shouldn't be on computers.

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  4. Re:PNG too? by Deviate_X · · Score: 5, Informative

    Some related exploits.

    Windows JPEG: Windows JPEG Processing Buffer Overrun PoC Exploit (MS04-028)

    Qt BMP: Qt 3.x bmp image parsing local buffer overflow Exploit

    XV BMP XV v3.x bmp parsing local buffer overflow Exploit

    GV Postscript: GV PostScript Viewer Remote Buffer overflow Exploit

    LibPNG: LibPNG Graphics Library Remote Buffer Overflow Exploit


  5. AutoUpdate not good enuff by DanMc · · Score: 5, Informative
    Autoupdate and Windowsupdate only install a fraction of the patches released for this bug. (Windows OS and IE basically)

    WindowsUpdate does install a "GDI+ Detection Tool", but I have run this tool on systems with unpatched Visual Studio, Outlook, and Office and it does not detect that the patches are missing. I looked at the strings in this tool, and it basically looks like it checks for MS Photo software.

    Manually visiting "officeupdate.microsoft.com" and running those updates will probably cover the most common attack vectors (Outlook, Word), but how many people do this on a regular basis? My users are not admin-level (yet) so they can't use this update site.

    Incidentally, every default configuration of IE/Word I have seen allows DOC files with jpegs to be opened in the browser window with no prompting. It will not be hard to get people to run the exploits, and there's plenty of ways for worms to automate themselves without users opening things.

    I'm working on a script to detect and run the patches (there's about 17 of them for this bug) but it's going to be a while because of the pre-reqs for many of the patches, and the very specific revisions that must match the patch. "If Visio 2002 is installed, detect which Visio SP level is running. If it's SP0 or SP1, run Visio SP2, then reboot, and run GDI patch"...

    Sorry if I'm spreading panic, but this bug sucks.