Attachment 15499 Details for Bug 15222 – MIT-SHM vulnerabilities draft advisory

MIT-SHM vulnerabilities draft advisory

pub_Multiple Vendor X Server MIT-SHM Extension Information Disclosure Vulnerability.txt (text/plain), 3.49 KB, created by Matthieu Herrb on 2008-03-27 03:38:00 UTC

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Creator: Matthieu Herrb

Created: 2008-03-27 03:38:00 UTC

Size: 3.49 KB

patch

obsolete

>iDefense Security Advisory XX.XX.XX
>http://labs.idefense.com/intelligence/vulnerabilities/
>MMM DD, YYYY
>
>I. BACKGROUND
>
>The X Window System is a graphical windowing system based on a
>client/server model. More information about about The X Window system
>is available at the following links.
>
>http://en.wikipedia.org/wiki/X_Window_System
>
>II. DESCRIPTION
>
>Local exploitation of an information disclosure vulnerability in the
>X.Org X server, as included in various vendors' operating system
>distributions, could allow an attacker to gain access to sensitive
>information stored in server memory.
>
>The vulnerability exists when creating a Pixmap in the fbShmPutImage()
>function. The width and height of the Pixmap, which are controlled by
>the user, are not properly validated to ensure that the Pixmap they
>define are within the bounds of the shared memory segment. This allows
>an attacker to read arbitrary areas of memory in the X Server process.
>
>III. ANALYSIS
>
>Exploitation allows an attacker to read arbitrary memory within the X
>Server's address space. By itself, the impact of this vulnerability is
>minimal. However, when coupled with a code execution vulnerability,
>this vulnerability can be used to greatly increase the reliability of
>an exploit. Additionally, this vulnerability can be used to crash the
>server. If the server automatically restarts, this can be useful since
>it resets the state of the server to a known state.
>
>If an X Server is configured to listen for TCP based client connections,
>and a client is granted access to create sessions (via the xhosts file),
>then the vulnerability can be exploited remotely.
>
>IV. DETECTION
>
>iDefense has confirmed the existence of this vulnerability in X.org X11
>version R7.3, with all patches as of 03/01/08 applied. Previous
>versions may also be affected.
>
>V. WORKAROUND
>
>Access to the vulnerable code can be prevented by preventing the X
>server from loading the MIT-SHM extension. However, doing so may impair
>the functionality of the server. Adding the following lines to the X
>configuration file will disable the MIT-SHM extension:
>
>Section "Extensions"   
>    Option "MIT-SHM" "disable"
>EndSection
>
>VI. VENDOR RESPONSE
>
>iDefense is currently working with the vendor to address this issue.
>Since there is no vendor fix at this time, please handle this
>information with sensitivity.
>
>VII. CVE INFORMATION
>
>A Mitre Corp. Common Vulnerabilities and Exposures (CVE) number has not
>been assigned yet.
>
>VIII. DISCLOSURE TIMELINE
>
>XX/XX/XXXX  Initial vendor notification
>
>IX. CREDIT
>
>This vulnerability was reported to iDefense by regenrecht.
>
>Get paid for vulnerability research
>http://labs.idefense.com/methodology/vulnerability/vcp.php
>
>Free tools, research and upcoming events
>http://labs.idefense.com/
>
>X. LEGAL NOTICES
>
>Copyright © 2008 iDefense, Inc.
>
>Permission is granted for the redistribution of this alert
>electronically. It may not be edited in any way without the express
>written consent of iDefense. If you wish to reprint the whole or any
>part of this alert in any other medium other than electronically,
>please e-mail customerservice@idefense.com for permission.
>
>Disclaimer: The information in the advisory is believed to be accurate
>at the time of publishing based on currently available information. Use
>of the information constitutes acceptance for use in an AS IS condition.
> There are no warranties with regard to this information. Neither the
>author nor the publisher accepts any liability for any direct,
>indirect, or consequential loss or damage arising from use of, or
>reliance on, this information.

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Attachments on bug 15222: 15497 | 15498 | 15499 | 15500 | 15614 | 16341 | 16473 | 16477 | 16478 | 16513 | 16793

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