Macromedia Flash SWF Denial of Service Vulnerability

Macromedia Flash is a modular package designed to enhance web browsing. A problem exists in the package that could cause a user's browser to crash.

The problem is in the handling of complex data by the Shockwave Flash plugin. Shockwave Flash files normally contain data in the format "tag length data." Complex data in a shockwave flash file contains data in the form of "tag length (subtag1 sublength1 subdata1 "0")". The plugin is dependent upon the ending "0" to signal the end of data and return to the main body of the file. If the placement of the zero exists beyond the specified "length" or "sublength" declaration, or doesn't exist at all, a read buffer overflow will occur that can allow a site with malicious flash content to crash browsers.

It is also reported that this issue results due to a buffer overflow that may allow for the arbitrary execution of code, but this claim is yet unverified.

This problem makes it possible for a user with malicious intent to crash browsers, resulting in a Denial of Service.


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