I. BACKGROUND
InstallAnywhere is a software framework that simplifies software installation on multiple client and server platforms. InstallAnywhere is utilized by vendors such as LimeWire (http://www.limewire.org). More information about InstallAnywhere is available at http://www.zerog.com.
II. DESCRIPTION
Zero G Software Inc.'s InstallAnywhere applications insecurely creates temporary files without checking for symbolic links allowing a local attacker to possibly overwrite any system file.
During installation the following temporary files are created:
/tmp/persistent_state
/tmp/env.properties.NNNNN
Where NNNNN represents the process id of the installation program. During installation InstallAnywhere does not check for symbolic links before opening the temporary files. An attacker can overwrite arbitrary system files by creating a symbolic link from one of the temporary files and then waiting for the super-user (root) to launch the InstallAnywhere installer.
As an example consider if an attacker were to create a symbolic link from /tmp/persistent_state to /etc/passwd:
$ ln -s /etc/passwd /tmp/persistent_state
Upon installation of InstallAnywhere by a user with write permissions to /etc/passwd that file would be overwritten.
III. ANALYSIS
An attacker with local system access and write access to /tmp can exploit the above-described vulnerability to clobber an arbitrary file.
iDEFENSE has proof of concept exploit code demonstrating the impact of this vulnerability.
IV. DETECTION
iDEFENSE has confirmed the existence of this vulnerability in InstallAnywhere Enterprise Edition 5.0.6 and 5.0.7. It is suspected that previous versions are vulnerable as well.
V. WORKAROUND
If possible when installing as root either boot into single user mode or temporarily remove group and other write permissions (chmod og-rwx /tmp) on the /tmp directory. Simply checking for the existence of exploiting symbolic links before installation is insufficient as a window of opportunity still exists for exploitation.
VI. VENDOR FIX
This issue has reportedly been addressed in the latest release of InstallAnywhere.
VII. CVE INFORMATION
A Mitre Corp. Common Vulnerabilities and Exposures (CVE) number has not been assigned to this issue.
VIII. DISCLOSURE TIMELINE
| 02/27/2003 |
Exploit acquired by iDEFENSE |
| 03/04/2003 |
Initial vendor notification |
| 06/06/2003 |
iDEFENSE Clients notified |
| 06/20/2003 |
Public Disclosure |
IX. CREDIT
This vulnerability is credited to Larry Cashdollar.
Get paid for vulnerability research
http://www.idefense.com/poi/teams/vcp.jsp
X. LEGAL NOTICES
Copyright © 2004 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
email 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.
