## Building a libc offset database Fetch all the configured libc versions and extract the symbol offsets. It will not download anything twice, so you can also use it to update your database: $ ./get You can also add a custom libc to your database. $ ./add /usr/lib/libc-2.21.so Find all the libc's in the database that have the given names at the given addresses. Only the last 12 bits are checked, because randomization usually works on page size level. $ ./find printf 260 puts f30 archive-glibc (id libc6_2.19-10ubuntu2_i386) Find a libc from the leaked return address into __libc_start_main. $ ./find __libc_start_main_ret a83 ubuntu-trusty-i386-libc6 (id libc6_2.19-0ubuntu6.6_i386) archive-eglibc (id libc6_2.19-0ubuntu6_i386) ubuntu-utopic-i386-libc6 (id libc6_2.19-10ubuntu2.3_i386) archive-glibc (id libc6_2.19-10ubuntu2_i386) archive-glibc (id libc6_2.19-15ubuntu2_i386) Dump some useful offsets, given a libc ID. You can also provide your own names to dump. $ ./dump libc6_2.19-0ubuntu6.6_i386 offset___libc_start_main_ret = 0x19a83 offset_system = 0x00040190 offset_dup2 = 0x000db590 offset_recv = 0x000ed2d0 offset_str_bin_sh = 0x160a24 Check whether a library is already in the database. $ ./identify /usr/lib/libc.so.6 id local-f706181f06104ef6c7008c066290ea47aa4a82c5