Process Injection: Thread Local Storage (T1055.005)
Tactics: Stealth, Privilege Escalation · Platforms: Windows
The interactive view maps 1 detection strategy, 1 mitigation, 2 software entries to this technique, alongside D3FEND countermeasures and data-component coverage.
Sub-technique of Process Injection (T1055).
Overview
Adversaries may inject malicious code into processes via thread local storage (TLS) callbacks in order to evade process-based defenses as well as possibly elevate privileges. TLS callback injection is a method of executing arbitrary code in the address space of a separate live process.
TLS callback injection involves manipulating pointers inside a portable executable (PE) to redirect a process to malicious code before reaching the code's legitimate entry point. TLS callbacks are normally used by the OS to setup and/or cleanup data used by threads. Manipulating TLS callbacks may be performed by allocating and writing to specific offsets within a process’ memory space using other Process Injection techniques such as Process Hollowing.
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 TLS callback injection may also evade detection from security products since the execution is masked under a legitimate process.