Detect Portable Executable Injection in CrowdStrike LogScale
Adversaries may inject portable executables (PE) into processes in order to evade process-based defenses as well as possibly elevate privileges. PE injection is commonly performed by copying code (perhaps without a file on disk) into the virtual address space of the target process before invoking it via a new thread. The write can be performed with native Windows API calls such as VirtualAllocEx and WriteProcessMemory, then invoked with CreateRemoteThread or additional code (ex: shellcode). Unlike DLL injection, PE injection copies the entire executable image into the target process rather than loading a DLL via LoadLibrary. The displacement of the injected code introduces the additional requirement for functionality to remap memory references.
MITRE ATT&CK
- Technique
- T1055 Process Injection
- Sub-technique
- T1055.002 Portable Executable Injection
- Canonical reference
- https://attack.mitre.org/techniques/T1055/002/
LogScale Detection Query
#event_simpleName=CreateRemoteThread
| SourceFileName != "MsMpEng.exe"
| SourceFileName != "csrss.exe"
| SourceFileName != "services.exe"
| SourceFileName != "svchost.exe"
| SourceFileName != "lsass.exe"
| SourceFileName != "wmiprvse.exe"
| not StartModule = /.+/
| StartModule := "(absent — PE injection indicator)"
| table([_timestamp, ComputerName, UserName, SourceProcessId, SourceFileName, TargetProcessId, TargetFileName, StartAddress, StartModule])
| sort(field=_timestamp, order=desc)CrowdStrike LogScale query targeting Sysmon CreateRemoteThread events ingested into LogScale (via Falcon LogScale Collector or a Sysmon forwarder) where StartModule is absent. The `not StartModule = /.+/` expression matches events where StartModule is empty or the field is not present, consistent with a thread entry point located in unmapped or PE-injected memory. If using native Falcon sensor telemetry instead of Sysmon, replace #event_simpleName=CreateRemoteThread with the appropriate Falcon injection telemetry event and update field references accordingly.
Data Sources
Required Tables
False Positives & Tuning
- CrowdStrike Falcon sensor operational events may themselves generate CreateRemoteThread telemetry without a StartModule during EDR monitoring operations
- Authorized red team tools (Cobalt Strike, Metasploit) running in sanctioned penetration testing engagements that test PE injection paths
- Some graphics driver subsystems and DirectX runtime components that create rendering threads in application processes without a populated StartModule field
Other platforms for T1055.002
Testing Methodology
Validate this detection against 3 adversary techniques from Atomic Red Team. Each test below lists the behaviour to exercise and the telemetry you should expect to see. Executable commands and cleanup steps are available with Pro.
- Test 1PE Injection via PowerShell with VirtualAllocEx and WriteProcessMemory
Expected signal: Sysmon Event ID 1: notepad.exe spawned by PowerShell. If full API chain used: Sysmon Event ID 10 (ProcessAccess) from PowerShell to notepad.exe with PROCESS_VM_WRITE rights. Sysmon Event ID 8 if CreateRemoteThread is called.
- Test 2Shellcode Injection via Donut Framework
Expected signal: When using the full Donut injection: Sysmon Event ID 8 (CreateRemoteThread) with empty StartModule. Sysmon Event ID 10 (ProcessAccess) with PROCESS_ALL_ACCESS. No corresponding Sysmon Event ID 7 (ImageLoad) in the target process.
- Test 3Process Injection using C# System.Diagnostics APIs
Expected signal: Sysmon Event ID 1: csc.exe spawned by PowerShell (compilation). Sysmon Event ID 11: pe_inject_test.exe created in TEMP. Sysmon Event ID 1: pe_inject_test.exe execution. Sysmon Event ID 1: notepad.exe spawned by pe_inject_test.exe.
References (5)
- https://attack.mitre.org/techniques/T1055/002/
- https://www.endgame.com/blog/technical-blog/ten-process-injection-techniques-technical-survey-common-and-trending-process
- https://github.com/redcanaryco/atomic-red-team/blob/master/atomics/T1055.002/T1055.002.md
- https://github.com/TheWover/donut
- https://www.elastic.co/blog/ten-process-injection-techniques-technical-survey-common-and-trending-process
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