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Cobalt Vulnerability Wiki

V5 - Validation/Sanitization

Rosetta Flash


The web application allows uploading an image file. Viewing the uploaded image is served through an Servlet that accepts encoding/language parameter. The attacker uploads a malicious flash file as an Image: "flashsniff.png" The attacker forge a malicious web page with the following payload

The hosting server will respond with the following headers: HTTP/1.1 200 OK .... X-Content-Type-Options: nosniff .... Content-Length: 733 Content-Type: image/png; charset=utf-8; lang=application/x-shockwave-flash

In this case Flash will execute malicious file types as flash applications even when X-Content-Type-Options: nosniff is on.