You still need an information leak of exact address of a libc function to achieve that, that will be different on every program invocation due to ASLR, and brut

You still need an information leak of exact address of a libc function to achieve that, that will be different on every program invocation due to ASLR, and brute forcing is useless on a 64bit memory space. Even information leaks about the location of other less useful libc functions + offset isn't enough, because OpenBSD randomly relinks libc every boot, so just having the libc of a release to harvest offset information isn't useful.