In-memory secrets
Theory
Just like the LSASS process on Windows systems allowing for LSASS dumping, some programs sometimes handle credentials in the memory allocated to their processes, sometimes allowing attackers to dump them.
Practice
Just like LSASS dumping, this technique needs the attacker to have admin access on the target machine since it involves dumping and handling volatile memory.
On UNIX-like systems, tools like mimipenguin (C, Shell, Python), mimipy (Python) and LaZagne (Python) can be used to extract passwords from memory.
bash
mimipenguin
laZagne memory