User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file.
The specific flaw exists within the parsing of the RIFF-based Director file format that Shockwave utilizes. When parsing such files, the code within the dirapi.dll module expects to find a chunk with a fourCC value of Lctx. The code does not consider the possibility that one may not exist and in that scenario if fails to properly initialize certain values that are used later on in parsing other chunks. By removing the Lctx chunk and also filling heap memory, an attacker can take advantage of the uninitialized values to write values to an arbitrary location in memory. This can be leveraged to execute remote code under the context of the user running the browser.
