Thread Local Storage - T1055.005 (e49ee9d2-0d98-44ef-85e5-5d3100065744)
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.(Citation: FireEye TLS Nov 2017)
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.
| Cluster A | Galaxy A | Cluster B | Galaxy B | Level |
|---|---|---|---|---|
| Thread Local Storage - T1055.005 (e49ee9d2-0d98-44ef-85e5-5d3100065744) | Attack Pattern | Process Injection - T1055 (43e7dc91-05b2-474c-b9ac-2ed4fe101f4d) | Attack Pattern | 1 |