Name Flash Parameter Injection
Summary An adversary takes advantage of improper data validation to inject malicious global parameters into a Flash file embedded within an HTML document. Flash files can leverage user-submitted data to configure the Flash document and access the embedding HTML document. These 'FlashVars' are most often passed to the Flash file via URL arguments or from the Object or Embed tag within the embedding HTML document. If these FlashVars are not properly sanitized, an adversary may be able to embed malicious content (such as scripts) into the HTML document. The injected parameters can also provide the adversary control over other objects within the Flash file as well as full control over the parent document's DOM model. As such, this is a form of HTTP parameter injection, but the abilities granted to the Flash document (such as access to a page's document model, including associated cookies) make this attack more flexible. Flash Parameter Injection attacks can also preface further attacks such as various forms of Cross-Site Scripting (XSS) attacks in addition to Session Hijacking attacks.
Prerequisites
Solutions User input must be sanitized according to context before reflected back to the user. The JavaScript function 'encodeURI' is not always sufficient for sanitizing input intended for global Flash parameters. Extreme caution should be taken when saving user input in Flash cookies. In such cases the Flash file itself will need to be fixed and recompiled, changing the name of the local shared objects (Flash cookies).
Related Weaknesses
CWE ID Description
CWE-88 Improper Neutralization of Argument Delimiters in a Command ('Argument Injection')
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