This whitepaper goes into detail on how to bypass tolower() filters in buffer overflows. It uses a stack-based buffer overflow as an example but the technique can also be applied to heap overflows as well.
Hope you guys enjoy it :).
The crash occurs when the application tries to write ECX (0x00000000) into the address that contains EAX (we control EAX) (0xBAADBEEF) . Possible explotable, not tested yet.
SHODAN Dork: "Server: Website/3.1"
Link: http://www.1337day.com/exploits/17806