Public Vulnerability Reports

Sun Microsystems Solaris NSPR Library Arbitrary File Creation Vulnerability



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


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.


Exploitation allows local attackers to elevate privileges to root.


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.


iDefense is currently unaware of any effective workaround for this


Sun Microsystems has addressed this issue with Sun Security Alert 102658
which can be found at:


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 (, which standardizes names for
security problems.


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


The discoverer of this vulnerability wishes to remain anonymous.

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Copyright © 2006 Verisign, Inc.

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