[VulnWatch] iDEFENSE Security Advisory 12.12.05: SCO Unixware Setuid 'uidadmin' Scheme Buffer Overflow Vulnerability



SCO Unixware Setuid 'uidadmin' Scheme Buffer Overflow Vulnerability

iDefense Security Advisory 12.12.05

www.iDefense.com/application/poi/display?id=350&type=vulnerabilities
December 12, 2005

I. BACKGROUND

SCO Unixware is a Unix operating system that runs on many OEM platforms.

II. DESCRIPTION

Local exploitation of a buffer overflow vulnerability in the uidadmin
binary included in multiple versions of The SCO Group Inc.'s Unixware
allows attackers to gain root privileges.

The vulnerability specifically exists because of a failure to check the
length of user specified file input. If the user prepares a file longer
than 1,600 bytes and supplies the path to that file using the "-S"
option of uidadmin, a stack based buffer overflow occurs. This leads to
the execution of arbitrary code with root privileges, as uidadmin is
setuid root by default.

III. ANALYSIS

Successful exploitation of this vulnerability requires that a user have
local access to the system. This would allow the user to gain super user
privileges.

IV. DETECTION

iDefense has confirmed the existence of this vulnerability in SCO
Unixware versions 7.1.3 and 7.1.4. All previous versions of SCO Unixware
are  suspected to be vulnerable.

V. WORKAROUND

Remove the setuid bit from the ppp binary:

 chmod u-s /unixware/usr/bin/uidadmin

VI. VENDOR RESPONSE

The vendor has released the following update to address this
vulnerability:

 ftp://ftp.sco.com/pub/updates/UnixWare/SCOSA-2005.54

VII. CVE INFORMATION

The Common Vulnerabilities and Exposures (CVE) project has assigned the
name CVE-2005-3903 to this issue. This is a candidate for inclusion in
the CVE list (http://cve.mitre.org), which standardizes names for
security problems.

VIII. DISCLOSURE TIMELINE

10/12/2005  Initial vendor notification
10/13/2005  Initial vendor response
12/12/2005  Coordinated public disclosure

IX. CREDIT

iDefense Labs is credited with the discovery of this vulnerability.

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X. LEGAL NOTICES

Copyright © 2005 iDefense, Inc.

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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.