Sun Microsystems Solaris NSPR Library Arbitrary File Creation Vulnerability

iDefense Security Advisory 10.11.06
http://www.idefense.com/intelligence/vulnerabilities/
Oct 11, 2006

I. BACKGROUND

The Netscape Portable Runtime (NSPR) API allows compliant applications
to use system facilities such as threads, thread synchronization, I/O,
interval timing, atomic operations and several other low-level services
in a platform-independent manner. More information can be found on
Mozilla's website at http://www.mozilla.org/projects/nspr/.

II. DESCRIPTION

Local exploitation of a design error vulnerability in version 4.6.1 of
NSPR, as included with Sun Microsystems Solaris 10, allows attackers to
create or overwrite arbitrary files on the system.

The problem exists because environment variables are used to create log
files. Even when the program is setuid, users can specify a log file
that will be created with elevated privileges.

III. ANALYSIS

Exploitation allows local attackers to elevate privileges to root.

IV. DETECTION

iDefense confirmed that Solaris 10 with NSPR version 4.6.1 is vulnerable
to privilege escalation. Additionally, iDefense has also confirmed via
the source code that version 4.6.2 does not address the vulnerability.

V. WORKAROUND

iDefense is currently unaware of any effective workaround for this
issue.

VI. VENDOR RESPONSE

Sun Microsystems has addressed this issue with Sun Security Alert 102658
which can be found at:
http://sunsolve.sun.com/search/document.do?assetkey=1-26-102658-1

VII. CVE INFORMATION

The Common Vulnerabilities and Exposures (CVE) project has assigned the
name CVE-2006-4842 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

08/31/2006  Initial vendor notification
09/04/2006  Initial vendor response
10/11/2006  Coordinated public disclosure

IX. CREDIT

The discoverer of this vulnerability wishes to remain anonymous.


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X. LEGAL NOTICES

Copyright © 2006 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
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