category binary exploitation - easy
solution The file we download is a ELF executable.
$ file ret2basic ret2basic: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked, interpreter /lib64/ld-linux-x86-64.so.2, BuildID[sha1]=3ca85eae693fed659275c0eed9c313e7f0083b85, for GNU/Linux 4.4.0, not stripped Running it hints the vuln.
$ ./ret2basic Can you overflow this?: AAAA Nope :( $ $ ./ret2basic Can you overflow this?: AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA  9615 segmentation fault ./ret2basic $ Disassembling the binary, we find that main() eventually calls vuln where the overflow exists....