ZDI-06-021: WebEx Downloader Plug-in Code Execution Vulnerability
http://www.zerodayinitiative.com/advisories/ZDI-06-021.html
July  6, 2006

-- CVE ID:
CVE-2006-3423

-- Affected Vendor:
WebEx Communications

-- Affected Products:
WebEx Downloader Plug-in (tested on v2.0.0.7)

-- TippingPoint(TM) IPS Customer Protection:
TippingPoint IPS customers have been protected against this
vulnerability since April  3, 2006 by Digital Vaccine protection
filter ID 4274. For further product information on the TippingPoint IPS:

    http://www.tippingpoint.com 

-- Vulnerability Details:
This vulnerability allows attackers to execute arbitrary code on
vulnerable installations of the WebEx Downloader Plug-in. Successful
exploitation requires that the target user browse to a malicious web
page.

The specific flaws exists due to the lack of input validation on
various ActiveX/Java control parameters and configuration directives.
The "GpcUrlRoot" and "GpcIniFileName" ActiveX/Java control parameters
allow an attacker to specify the location of a configuration file
containing further control directives. This allows an attacker to
transfer arbitrary files and executables to the target. The attacker
can then leverage available configuration directives to execute the
newly created executables thereby compromising the underlying system.

-- Vendor Response:
WebEx has addressed this issue in the latest release of the Downloader
plug-in. More informaton is available from the vendor advisory
(#WEBX-06-1-1) at:

http://www.webex.com/lp/security/ActiveAdv.html?TrackID=123456

-- Disclosure Timeline:
2006.04.03 - Digital Vaccine released to TippingPoint customers
2006.04.11 - Vulnerability reported to vendor
2006.07.06 - Coordinated public release of advisory

-- Credit:
This vulnerability was discovered by an anonymous researcher.

-- About the Zero Day Initiative (ZDI):
Established by TippingPoint, a division of 3Com, The Zero Day Initiative
(ZDI) represents a best-of-breed model for rewarding security
researchers for responsibly disclosing discovered vulnerabilities.

Researchers interested in getting paid for their security research
through the ZDI can find more information and sign-up at:

    http://www.zerodayinitiative.com

The ZDI is unique in how the acquired vulnerability information is used.
3Com does not re-sell the vulnerability details or any exploit code.
Instead, upon notifying the affected product vendor, 3Com provides its
customers with zero day protection through its intrusion prevention
technology. Explicit details regarding the specifics of the
vulnerability are not exposed to any parties until an official vendor
patch is publicly available. Furthermore, with the altruistic aim of
helping to secure a broader user base, 3Com provides this vulnerability
information confidentially to security vendors (including competitors)
who have a vulnerability protection or mitigation product.