Proc Memory

What the technique is

Adversaries may inject malicious code into processes via the /proc filesystem in order to evade process-based defenses as well as possibly elevate privileges. Proc memory injection is a method of executing arbitrary code in the address space of a separate live process. Proc memory injection involves enumerating the memory of a process via the /proc filesystem (/proc/[pid]) then crafting a return-oriented programming (ROP) payload with available gadgets/instructions. Each running process has its own directory, which includes memory mappings. Proc memory injection is commonly performed by overwriting the target processes’ stack using memory mappings provided by the /proc filesystem. This information can be used to enumerate offsets (including the stack) and gadgets (or instructions within the program that can be used to build a malicious payload) otherwise hidden by process memory protections such as address space layout randomization (ASLR). Once enumerated, the target processes’ memory map within /proc/[pid]/maps can be overwritten using dd. Other techniques such as Dynamic Linker Hijacking may be used to populate a target process with more available gadgets. Similar to Process Hollowing, proc memory injection may target child processes (such as a backgrounded copy of sleep). […]

What MITRE says you would watch

• AN1494

  Detects adversary behavior where a process enumerates and modifies another process's memory using /proc/[pid]/maps and /proc/[pid]/mem files. This includes identifying gadgets via memory mappings and overwriting process memory via low-level file modification or dd usage.