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).
Running code in the context of another process may allow access to the process's memory, system/network resources, and possibly elevated privileges. Execution via proc memory injection may also evade detection from security products since the execution is masked under a legitimate process.
|M1040||Behavior Prevention on Endpoint||
Some endpoint security solutions can be configured to block some types of process injection based on common sequences of behavior that occur during the injection process.
|M1022||Restrict File and Directory Permissions||
Restrict the permissions on sensitive files such as
|ID||Data Source||Data Component|
File system monitoring can determine if /proc files are being modified. Users should not have permission to modify these in most cases.
Analyze process behavior to determine if a process is performing actions it usually does not, such as opening network connections, reading files, or other suspicious actions that could relate to post-compromise behavior.