comments (not for humans)
Unrestricted crossdomain.xml and clientaccesspolicy.xml files can be abused by malicious RIAs - or MalaRIAs - to perform actions on behalf of the user. For this PoC (proof of concept) I setup a malicious RIA to act as a proxy by comibining it with a server side application. This would allow the attacker to use the combined solution as a proxy and surf web sites with unrestricted cross domain policies through the victim's browser.

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Most web browsers implement the Same Origin Policy which limits how javascript etc. can interact across domains. Without this policy an attacker could setup a site, and if tricked into visiting it, the attacker could read data from all your logged in sessions (gmail, banking etc.) and perform actions against those sites on your behalf. This policy was seen as a bit to restrictive for flash/flex/silverlight which may need to read data from other domains. Adobe introduced the cross domain policy to address this concern. Unfortunately a lot of sites are not paying attention to what this policy really means.
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