Typical allocator free() calls don't actually overwrite the memory, meaning that the data stays there until it happens to get overwritten by a future process, w

Typical allocator free() calls don't actually overwrite the memory, meaning that the data stays there until it happens to get overwritten by a future process, which is an unpredictable event. When I was doing research on the cold boot attacks I did a lot of "strings /dev/mem" and would notice stuff related to things I was working on several days ago. As our cold boot paper described, this could sometimes include things that you were doing even before the computer was last rebooted. There is a really nice paper on this particular topic https://benpfaff.org/papers/shredding.html/index.html https://benpfaff.org/papers/shredding.html/index.html which describes some useful countermeasures which haven't been widely implemented. If they had been, they could have somewhat reduced the impact of opportunistic exploitation of memory disclosure vulnerabilities.