T1055.003: Thread Execution Hijacking

Adversaries may inject malicious code into hijacked processes in order to evade process-based defenses as well as possibly elevate privileges. Thread Execution Hijacking is a method of executing arbitrary code in the address space of a separate live process.

Thread Execution Hijacking is commonly performed by suspending an existing process then unmapping/hollowing its memory, which can then be replaced with malicious code or the path to a DLL. A handle to an existing victim process is first created with native Windows API calls such as OpenThread. At this point the process can be suspended then written to, realigned to the injected code, and resumed via SuspendThread , VirtualAllocEx, WriteProcessMemory, SetThreadContext, then ResumeThread respectively.

This is very similar to Process Hollowing but targets an existing process rather than creating a process in a suspended state.

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 Thread Execution Hijacking may also evade detection from security products since the execution is masked under a legitimate process.

Positive Technologies products that cover the technique

MaxPatrol SIEM knowledge base

mitre_attck_cred_access: PT-CR-1074: Create_Remote_Thread_Into_LSASS: A thread is created in the address space of the lsass.exe process
mitre_attck_defense_evasion: PT-CR-781: TikiTorch_Process_Injection: Process injection using TikiTorch is detected
mitre_attck_defense_evasion: PT-CR-933: Malicious_Activity_From_Office_Documents: The following suspicious activity of office programs is detected: creating executables, changing registry keys, loading the DLL of an Internet Explorer COM object, creating threads in other processes' address space
mitre_attck_defense_evasion: PT-CR-2222: Proccess_Tampering: A process created a thread in the address space of a process. Attackers inject code into processes to bypass process-based security or escalate privileges.

Detection

ID	DS0009	Data source and component	Process: OS API Execution	Description	Monitoring Windows API calls indicative of the various types of code injection may generate a significant amount of data and may not be directly useful for defense unless collected under specific circumstances for known bad sequences of calls, since benign use of API functions may be common and difficult to distinguish from malicious behavior. Windows API calls such as `CreateRemoteThread`, `SuspendThread`/`SetThreadContext`/`ResumeThread`, and those that can be used to modify memory within another process, such as `VirtualAllocEx`/`WriteProcessMemory`, may be used for this technique.

ID	DS0009	Data source and component	Process: Process Modification	Description	Monitor for changes made to processes that may inject malicious code into hijacked processes in order to evade process-based defenses as well as possibly elevate privileges.

ID	DS0009	Data source and component	Process: Process Access	Description	Monitor for processes being viewed that may inject malicious code into hijacked processes in order to evade process-based defenses as well as possibly elevate privileges.

ID	Data source and component	Description
DS0009	Process: OS API Execution	Monitoring Windows API calls indicative of the various types of code injection may generate a significant amount of data and may not be directly useful for defense unless collected under specific circumstances for known bad sequences of calls, since benign use of API functions may be common and difficult to distinguish from malicious behavior. Windows API calls such as `CreateRemoteThread`, `SuspendThread`/`SetThreadContext`/`ResumeThread`, and those that can be used to modify memory within another process, such as `VirtualAllocEx`/`WriteProcessMemory`, may be used for this technique.
DS0009	Process: Process Modification	Monitor for changes made to processes that may inject malicious code into hijacked processes in order to evade process-based defenses as well as possibly elevate privileges.
DS0009	Process: Process Access	Monitor for processes being viewed that may inject malicious code into hijacked processes in order to evade process-based defenses as well as possibly elevate privileges.

Mitigation

ID	M1040	Name	Behavior Prevention on Endpoint	Description	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.

ID	Name	Description
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.