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T1631.001 Ptrace System Calls

Adversaries may inject malicious code into processes via ptrace (process trace) system calls in order to evade process-based defenses as well as possibly elevate privileges. Ptrace system call injection is a method of executing arbitrary code in the address space of a separate live process.

Ptrace system call injection involves attaching to and modifying a running process. The ptrace system call enables a debugging process to observe and control another process (and each individual thread), including changing memory and register values.3 Ptrace system call injection is commonly performed by writing arbitrary code into a running process (e.g., by using malloc) then invoking that memory with PTRACE_SETREGS to set the register containing the next instruction to execute. Ptrace system call injection can also be done with PTRACE_POKETEXT/PTRACE_POKEDATA, which copy data to a specific address in the target process’s memory (e.g., the current address of the next instruction).32

Ptrace system call injection may not be possible when targeting processes with high-privileges, and on some systems those that are non-child processes.1

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 ptrace system call injection may also evade detection from security products since the execution is masked under a legitimate process.

Item Value
ID T1631.001
Sub-techniques T1631.001
Tactics TA0030, TA0029
Platforms Android, iOS
Version 1.1
Created 30 March 2022
Last Modified 20 March 2023

Procedure Examples

ID Name Description
S0463 INSOMNIA INSOMNIA grants itself permissions by injecting its hash into the kernel’s trust cache.7
S0424 Triada Triada injects code into the Zygote process to effectively include itself in all forked processes. Additionally, code is injected into the Android Play Store App, web browser applications, and the system UI application.56
S0494 Zen Zen can inject code into the Setup Wizard at runtime to extract CAPTCHA images. Zen can inject code into the libc of running processes to infect them with the malware.4


ID Data Source Data Component
DS0041 Application Vetting API Calls