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.