ZDI-09-049: Sun Java Pack200 Decoding Inner Class Count Integer Overflow
Vulnerability
http://www.zerodayinitiative.com/advisories/ZDI-09-049
August 5, 2009

-- Affected Vendors:
Sun Microsystems

-- Affected Products:
Sun Microsystems Java Runtime

-- Vulnerability Details:
This vulnerability allows remote attackers to execute arbitrary code on
vulnerable installations of the Sun Java Runtime. User interaction is
required in that a target must visit a malicious web page or open a
malicious JNLP file.

The specific flaw exists within the code responsible for handling
Pack200 compressed JAR files. During decompression, several fields
within a Pack200 header are trusted and used to calculate sizes for heap
buffer allocations. By providing malicious values an attacker can create
undersized heap buffers and subsequently overflow them. This can be
leveraged to execute arbitrary code under the context of the user
accessing the file or web page.

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

http://sunsolve.sun.com/search/document.do?assetkey=1-66-263488-1

-- Disclosure Timeline:
2009-04-15 - Vulnerability reported to vendor
2009-08-05 - Coordinated public release of advisory

-- Credit:
This vulnerability was discovered by:
    * Anonymous

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