Description
Adversaries may inject malicious code into suspended and hollowed processes in order to evade process-based defenses. Process hollowing is a method of executing arbitrary code in the address space of a separate live process.
Process hollowing is commonly performed by creating a process in a suspended state then unmapping/hollowing its memory, which can then be replaced with malicious code. A victim process can be created with native Windows API calls such as CreateProcess, which includes a flag to suspend the processes primary thread. At this point the process can be unmapped using APIs calls such as ZwUnmapViewOfSection or NtUnmapViewOfSection before being written to, realigned to the injected code, and resumed via VirtualAllocEx, WriteProcessMemory, SetThreadContext, then ResumeThread respectively.(Citation: Leitch Hollowing)(Citation: Elastic Process Injection July 2017)
This is very similar to Thread Local Storage but creates a new process rather than targeting an existing process. This behavior will likely not result in elevated privileges since the injected process was spawned from (and thus inherits the security context) of the injecting process. However, execution via process hollowing may also evade detection from security products since the execution is masked under a legitimate process.
Platforms
Mitigations (1)
Behavior Prevention on EndpointM1040
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.
Threat Groups (8)
| ID | Group | Context |
|---|---|---|
| G1043 | BlackByte | [BlackByte](https://attack.mitre.org/groups/G1043) used process hollowing for defense evasion purposes.(Citation: Microsoft BlackByte 2023) |
| G0094 | Kimsuky | [Kimsuky](https://attack.mitre.org/groups/G0094) has used a file injector DLL to spawn a benign process on the victim's system and inject the maliciou... |
| G0040 | Patchwork | A [Patchwork](https://attack.mitre.org/groups/G0040) payload uses process hollowing to hide the UAC bypass vulnerability exploitation inside svchost.e... |
| G0078 | Gorgon Group | [Gorgon Group](https://attack.mitre.org/groups/G0078) malware can use process hollowing to inject one of its trojans into another process.(Citation: U... |
| G0045 | menuPass | [menuPass](https://attack.mitre.org/groups/G0045) has used process hollowing in iexplore.exe to load the [RedLeaves](https://attack.mitre.org/software... |
| G1018 | TA2541 | [TA2541](https://attack.mitre.org/groups/G1018) has used process hollowing to execute CyberGate malware.(Citation: Cisco Operation Layover September 2... |
| G0099 | APT-C-36 | [APT-C-36](https://attack.mitre.org/groups/G0099) has used process hollowing to execute malware in the memory of legitimate processes.(Citation: Kaspe... |
| G0027 | Threat Group-3390 | A [Threat Group-3390](https://attack.mitre.org/groups/G0027) tool can spawn `svchost.exe` and inject the payload into that process.(Citation: Nccgroup... |
Associated Software (35)
| ID | Name | Type | Context |
|---|---|---|---|
| S0266 | TrickBot | Malware | [TrickBot](https://attack.mitre.org/software/S0266) injects into the svchost.exe process.(Citation: S2 Grupo TrickBot June 2017)(Citation: Trend Micro... |
| S0662 | RCSession | Malware | [RCSession](https://attack.mitre.org/software/S0662) can launch itself from a hollowed svchost.exe process.(Citation: Secureworks BRONZE PRESIDENT Dec... |
| S0229 | Orz | Malware | Some [Orz](https://attack.mitre.org/software/S0229) versions have an embedded DLL known as MockDll that uses process hollowing and [Regsvr32](https://... |
| S0226 | Smoke Loader | Malware | [Smoke Loader](https://attack.mitre.org/software/S0226) spawns a new copy of c:\windows\syswow64\explorer.exe and then replaces the executable code in... |
| S9018 | HeartCrypt | Malware | For .NET payloads, [HeartCrypt](https://attack.mitre.org/software/S9018) can use process hollowing to inject into processes spawned by csc.exe or AppL... |
| S0386 | Ursnif | Malware | [Ursnif](https://attack.mitre.org/software/S0386) has used process hollowing to inject into child processes.(Citation: FireEye Ursnif Nov 2017) |
| S0198 | NETWIRE | Malware | The [NETWIRE](https://attack.mitre.org/software/S0198) payload has been injected into benign Microsoft executables via process hollowing.(Citation: Fi... |
| S0367 | Emotet | Malware | [Emotet](https://attack.mitre.org/software/S0367) uses a copy of `certutil.exe` stored in a temporary directory for process hollowing, starting the pr... |
| S1138 | Gootloader | Malware | [Gootloader](https://attack.mitre.org/software/S1138) can inject its Delphi executable into ImagingDevices.exe using a process hollowing technique.(Ci... |
| S1065 | Woody RAT | Malware | [Woody RAT](https://attack.mitre.org/software/S1065) can create a suspended notepad process and write shellcode to delete a file into the suspended pr... |
| S1086 | Snip3 | Malware | [Snip3](https://attack.mitre.org/software/S1086) can use RunPE to execute malicious payloads within a hollowed Windows process.(Citation: Morphisec S... |
| S0689 | WhisperGate | Malware | [WhisperGate](https://attack.mitre.org/software/S0689) has the ability to inject its fourth stage into a suspended process created by the legitimate W... |
| S1130 | Raspberry Robin | Malware | [Raspberry Robin](https://attack.mitre.org/software/S1130) will execute a legitimate process, then suspend it to inject code for a [Tor](https://attac... |
| S0483 | IcedID | Malware | [IcedID](https://attack.mitre.org/software/S0483) can inject a [Cobalt Strike](https://attack.mitre.org/software/S0154) beacon into cmd.exe via proces... |
| S0189 | ISMInjector | Malware | [ISMInjector](https://attack.mitre.org/software/S0189) hollows out a newly created process RegASM.exe and injects its payload into the hollowed proces... |
| S0127 | BBSRAT | Malware | [BBSRAT](https://attack.mitre.org/software/S0127) has been seen loaded into msiexec.exe through process hollowing to hide its execution.(Citation: Pal... |
| S1213 | Lumma Stealer | Malware | [Lumma Stealer](https://attack.mitre.org/software/S1213) has used process hollowing leveraging a legitimate program such as “BitLockerToGo.exe” to inj... |
| S0660 | Clambling | Malware | [Clambling](https://attack.mitre.org/software/S0660) can execute binaries through process hollowing.(Citation: Trend Micro DRBControl February 2020) |
| S1111 | DarkGate | Malware | [DarkGate](https://attack.mitre.org/software/S1111) leverages process hollowing techniques to evade detection, such as decrypting the content of an en... |
| S1018 | Saint Bot | Malware | The [Saint Bot](https://attack.mitre.org/software/S1018) loader has used API calls to spawn `MSBuild.exe` in a suspended state before injecting the de... |
Related CWE Weaknesses
References
- Hosseini, A. (2017, July 18). Ten Process Injection Techniques: A Technical Survey Of Common And Trending Process Injection Techniques. Retrieved December 7, 2017.
- Leitch, J. (n.d.). Process Hollowing. Retrieved September 12, 2024.
Frequently Asked Questions
What is T1055.012 (Process Hollowing)?
T1055.012 is a MITRE ATT&CK technique named 'Process Hollowing'. It belongs to the Stealth, Privilege Escalation tactic(s). Adversaries may inject malicious code into suspended and hollowed processes in order to evade process-based defenses. Process hollowing is a method of executing arbitrary code in the address space of...
How can T1055.012 be detected?
Detection of T1055.012 (Process Hollowing) typically involves monitoring system logs, network traffic, and endpoint telemetry. Use SIEM rules, EDR solutions, and behavioral analytics to identify suspicious activity associated with this technique.
What mitigations exist for T1055.012?
There are 1 documented mitigations for T1055.012. Key mitigations include: Behavior Prevention on Endpoint.
Which threat groups use T1055.012?
Known threat groups using T1055.012 include: BlackByte, Kimsuky, Patchwork, Gorgon Group, menuPass, TA2541, APT-C-36, Threat Group-3390.