ZDI-07-015: Novell Groupwise WebAccess Base64 Decoding Stack Overflow Vulnerability

[zdi-disclosures@xxxxxxxx]

ZDI-07-015: Novell Groupwise WebAccess Base64 Decoding Stack Overflow
            Vulnerability
http://www.zerodayinitiative.com/advisories/ZDI-07-015.html
April 18, 2007

-- CVE ID:
CVE-2007-2171

-- Affected Vendor:
Novell

-- Affected Products:
Groupwise WebAccess

-- TippingPoint(TM) IPS Customer Protection:
TippingPoint IPS customers have been protected against this
vulnerability since April 19, 2007 by Digital Vaccine protection
filter ID 5295. For further product information on the TippingPoint IPS:

    http://www.tippingpoint.com 

-- Vulnerability Details:
This vulnerability allows remote attackers to execute arbitrary code on
vulnerable installations of Novell Groupwise WebAccess. Authentication
is not required to exploit this vulnerability.

The specific flaw exists in the GWINTER.exe process bound by default on
TCP ports 7205 and 7211. During the handling of an HTTP Basic
authentication request, the process copies user-supplied base64 data
into a fixed length stack buffer. Sending at least 336 bytes will
trigger a stack based buffer overflow due to a vulnerable
base64_decode() call. Exploitation of this issue can result in
arbitrary code execution.

-- Vendor Response:
Novell has issued an update to correct this vulnerability. More details
can be found at:

    http://download.novell.com/Download?buildid=8RF83go0nZg~
    http://download.novell.com/Download?buildid=O9ucpbS1bK0~

-- Disclosure Timeline:
2007.03.19 - Vulnerability reported to vendor
2007.04.18 - Coordinated public release of advisory
2007.04.19 - Digital Vaccine released to TippingPoint customers

-- Credit:
This vulnerability was discovered by Tenable Network Security.

-- 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.