TippingPoint Zero Day Initiative
 

RealNetworks Helix Server NTLM Authentication Malformed Base64 Heap Overflow Vulnerability

ZDI-08-091: December 16th, 2008

CVE ID

Affected Vendors

Affected Products

    Helix Server

TippingPoint™ IPS Customer Protection

TippingPoint IPS customers are protected against this vulnerability by Digital Vaccine protection filter ID 6378. For further product information on the TippingPoint IPS:

Vulnerability Details

This vulnerability allows remote attackers to execute arbitrary code on systems with vulnerable installations of RealNetworks Helix Server. Authentication is not required to exploit this vulnerability.

The specific flaw exists during NTLM negotiation. The function responsible for decoding Base64 will return a length value on success and 0xFFFFFFFF on failure. The variable used for the return value is unsigned and is interpreted as an actual length value later on. This discrepancy leads to a heap overflow while attempting to copy 0xFFFFFFFF bytes worth of data. Exploitation leads to arbitrary code execution under the context of the SYSTEM user.

Vendor Response

RealNetworks states:


Disclosure Timeline

    2008-08-19 - Vulnerability reported to vendor
    2008-12-16 - Coordinated public release of advisory

Credit

This vulnerability was discovered by:
    Anonymous