Home    |    View Topics    |    Search    |    Contact Us    |   



Category:   OS (UNIX)  >   FreeBSD Kernel Vendors:   FreeBSD
FreeBSD Kernel i386_set_ldt() Integer Overflow Lets Local Users Deny Service
SecurityTracker Alert ID:  1016926
SecurityTracker URL:
CVE Reference:   CVE-2006-4172   (Links to External Site)
Date:  Sep 26 2006
Impact:   Denial of service via local system
Fix Available:  Yes  Vendor Confirmed:  Yes  
Version(s): 5.5, possibly earlier versions
Description:   iDEFENSE reported a vulnerability in FreeBSD kernel in the i386_set_ldt() function. A local user can cause denial of service conditions.

A local user can trigger an integer overflow to cause a kernel panic.

iDEFENSE reported this vulnerability.

Impact:   A local user can cause a kernel panic.
Solution:   The vendor issued a source code correction on March 23, 2005.
Vendor URL: (Links to External Site)
Cause:   Boundary error, Input validation error

Message History:   None.

 Source Message Contents

Subject:  iDefense Security Advisory 09.23.06: FreeBSD i386_set_ldt Integer

FreeBSD i386_set_ldt Integer Overflow Vulnerability

iDefense Security Advisory 09.23.06
Sep 23, 2006


FreeBSD is a modern operating system for x86, amd64, Alpha, IA-64, PC-98
and SPARC architectures. It's based on the UNIX operating system, BSD,
which was created at the University of California, Berkeley.  More
information can be obtained from the FreeBSD Project web site at


Local exploitation of a input validation error in the FreeBSD Project's
i386_set_ldt() kernel implementation could allow attackers to create a
kernel panic, leading to a denial of service condition on the affected


Exploitation of this vulnerability would result in a denial of service
condition on the affected host.  There is a potential for arbitrary code
execution in kernel context due to the way this function manipulates
kernel heap memory. 


iDefense has confirmed the existence of this problem in FreeBSD 5.5. It
is suspected that versions as early as 5.2 are also affected.


iDefense is not aware of any workaround for this issue.


"It appears that the problem you have discovered was fixed in revision
1.96 of src/sys/i386/i386/sys_machdep.c on March 23, 2005, after being
found by the Coverity Prevent analysis tool; the commit message at the
time documented this as a local denial of service bug.

The policy of the FreeBSD Security Team is that local denial of service bugs
not be treated as security issues; it is possible that this problem will be
corrected in a future Erratum."


The Common Vulnerabilities and Exposures (CVE) project has assigned the
name CVE-2006-4172 to this issue. This is a candidate for inclusion in
the CVE list (, which standardizes names for
security problems.


08/16/2006  Initial vendor notification
08/16/2006  Initial vendor response
09/23/2006  Public disclosure


The discoverer of this vulnerability wishes to remain anonymous.

Get paid for vulnerability research

Free tools, research and upcoming events


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
email 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.

To unsubscribe, go here:

Go to the Top of This SecurityTracker Archive Page

Home   |    View Topics   |    Search   |    Contact Us

This web site uses cookies for web analytics. Learn More

Copyright 2019, LLC