Nibble Security: The old is new, again. CVE-2011-2461: As part of an ongoing investigation on Adobe Flash SOP bypass techniques, we identified a vulnerability affecting old releases of the Adobe Flex SDK compiler. Further investigation traced the issue back to a known vulnerability (CVE-2011-2461), already patched by Adobe in apsb11-25.
Old vulnerability, bad luck, let’s move on. Not this time.
The particularity of CVE-2011-2461 is that vulnerable Flex applications have to be recompiled or patched; even with the most recent Flash player, vulnerable Flex applications can be exploited. As long as the SWF file was compiled with a vulnerable Flex SDK, attackers can still use this vulnerability against the latest web browsers and Flash plugin.
As soon as we understood the potential risk, we conducted a large-scale analysis by locating SWFs hosted on popular websites and analyzing those files with a custom tool capable of detecting vulnerable code patterns. This research has led to the identification of numerous websites vulnerable to CVE-2011-2461, including 3 sites out of the Alexa Top 10.