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Apple Mac OS X help system may interpret inappropriate local script files

Vulnerability Note VU#578798

Original Release Date: 2004-05-21 | Last Revised: 2004-05-24

Overview

A vulnerability has been reported in the default URI protocol handler in Apple's Mac OS X help system. Exploitation of this vulnerability may permit a remote attacker to execute arbitrary scripts on the local system.

Description

A vulnerability has been reported in Apple's Mac OS X runscript function of the Help.app application. Using the "help://" URI handler, a remote attacker may be able to create an HTML file that will execute local scripts on the target user's system. If exploited conjunction with VU#210606, a remote attacker may be able to execute arbitrary code of the attacker's choosing. Browsers or other applications supporting this help system URI handler enabled by default on Mac OS X have been reported to be vulnerable.

Impact

A remote attacker may be able to run arbitrary files with interpretable script on a vulnerable system.

Solution

Download updated software per Apple's Security Update notice:

* Apple's Software Downloads web site:

For Mac OS X 10.3.3 "Panther" and Mac OS X 10.3.3 Server
========================================================
http://www.apple.com/support/downloads/securityupdate__2004-05-24_(10_3_3).html
The download file is named: "SecUpd2004-05-24Pan.dmg"
Its SHA-1 digest is: 8e505ac4e36393f44e9d1b27ac0bd9a9e9f5b6a2

For Mac OS X 10.2.8 "Jaguar" and Mac OS X 10.2.8 Server
=======================================================
http://www.apple.com/support/downloads/securityupdate_2004-05-24_(10_2_8).html
The download file is named: "SecUpd2004-05-24Jag.dmg"
Its SHA-1 digest is: 8c084551505fb4e7131afbf8bce14475bdc5f946

According to a posting on Secunia, users may be able to mitigate the potential impact of this reported vulnerability by changing the protocol helpers (applications) for URI handlers which are not required, (e.g., disable "help://" execution).

Vendor Information

578798
 
Affected   Unknown   Unaffected

Apple Computer Inc.

Notified:  May 21, 2004 Updated:  May 24, 2004

Status

  Vulnerable

Vendor Statement

No statement is currently available from the vendor regarding this vulnerability.

Vendor Information

The vendor has not provided us with any further information regarding this vulnerability.

Addendum

Please see APPLE-SA-2004-05-21 Security Update 2004-05-24:

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

APPLE-SA-2004-05-21 Security Update 2004-05-24

Security Update 2004-05-24 is now available and contains security
enhancements for the following:

HelpViewer: Fixes CAN-2004-0486 to ensure that HelpViewer will only
process scripts that it initiated. Credit to lixlpixel
<me@lixlpixel.com> for reporting this issue. This issue has been
widely reported as a problem with the Safari web browser, but can
affect other web browsers. This update will fix the issue for Safari
and other web browsers.

Terminal: Fixes CAN-2004-0485 to improve URL processing within
Terminal. Credit to Reni Puls <rpuls@gmx.net> for reporting this
issue.

================================================

Security Update 2004-05-24 may be obtained from:

* Software Update pane in System Preferences

* Apple's Software Downloads web site:

For Mac OS X 10.3.3 "Panther" and Mac OS X 10.3.3 Server
========================================================
http://www.apple.com/support/downloads/securityupdate__2004-05-24_(
10_3_3).html
The download file is named: "SecUpd2004-05-24Pan.dmg"
Its SHA-1 digest is: 8e505ac4e36393f44e9d1b27ac0bd9a9e9f5b6a2

For Mac OS X 10.2.8 "Jaguar" and Mac OS X 10.2.8 Server
=======================================================
http://www.apple.com/support/downloads/securityupdate_2004-05-24_(
10_2_8).html
The download file is named: "SecUpd2004-05-24Jag.dmg"
Its SHA-1 digest is: 8c084551505fb4e7131afbf8bce14475bdc5f946

Information will also be posted to the Apple Product Security web
site:
http://www.apple.com/support/security/security_updates.html

This message is signed with Apple's Product Security PGP key, and
details are available at:
http://www.apple.com/support/security/security_pgp.html

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If you have feedback, comments, or additional information about this vulnerability, please send us email.


CVSS Metrics

Group Score Vector
Base N/A N/A
Temporal N/A N/A
Environmental N/A

References

Acknowledgements

Thanks to Kang for reporting this vulnerability.

This document was written by Jason A Rafail and is based on information from Secunia.com and SecurityTracker.com.

Other Information

CVE IDs: CVE-2004-0486
Severity Metric: 19.89
Date Public: 2004-05-17
Date First Published: 2004-05-21
Date Last Updated: 2004-05-24 17:43 UTC
Document Revision: 9

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