Anthropic-Cybersecurity-Skills/skills/detecting-t1055-process-injection-with-sysmon/references/api-reference.md

API Reference: T1055 Process Injection Detection with Sysmon

MITRE ATT&CK T1055 Sub-Techniques

Sub-technique	Method	Sysmon Event
T1055.001	DLL Injection	Event 7, 8, 10
T1055.002	PE Injection	Event 8, 10
T1055.003	Thread Execution Hijacking	Event 8
T1055.004	Asynchronous Procedure Call	Event 8, 10
T1055.005	Thread Local Storage	Event 8
T1055.012	Process Hollowing	Event 1, 10, 25

Sysmon Event IDs

Event 8 — CreateRemoteThread

Field	Index	Description
SourceProcessGuid	1	GUID of injecting process
SourceProcessId	2	PID of injecting process
SourceImage	4	Path of injecting binary
TargetProcessGuid	5	GUID of target process
TargetProcessId	6	PID of target process
TargetImage	7	Path of target binary
StartAddress	8	Thread start address
StartFunction	9	Thread entry function

Event 10 — ProcessAccess

Field	Index	Description
SourceProcessId	3	Accessing PID
SourceImage	4	Accessing binary path
TargetProcessId	7	Accessed PID
TargetImage	8	Accessed binary path
GrantedAccess	10	Access rights mask

Event 7 — Image Loaded

Field	Index	Description
Image	3	Process that loaded DLL
ImageLoaded	5	DLL path
Signed	6	Signature status
SignatureStatus	8	Valid/Invalid/Unknown

Process Access Masks

Mask	Right	Injection Use
0x0008	PROCESS_VM_OPERATION	VirtualAllocEx
0x0010	PROCESS_VM_READ	ReadProcessMemory
0x0020	PROCESS_VM_WRITE	WriteProcessMemory
0x0800	PROCESS_SUSPEND_RESUME	Hollowing
0x001F0FFF	PROCESS_ALL_ACCESS	Full control

Sysmon Configuration for Injection Detection

<Sysmon>
  <EventFiltering>
    <ProcessAccess onmatch="include">
      <GrantedAccess condition="is">0x1F0FFF</GrantedAccess>
      <GrantedAccess condition="is">0x001F0FFF</GrantedAccess>
    </ProcessAccess>
    <CreateRemoteThread onmatch="exclude">
      <SourceImage condition="is">C:\Windows\System32\svchost.exe</SourceImage>
    </CreateRemoteThread>
  </EventFiltering>
</Sysmon>

Sigma Rule Example

title: CreateRemoteThread into System Process
logsource:
    product: windows
    category: create_remote_thread
detection:
    selection:
        TargetImage|endswith:
            - '\svchost.exe'
            - '\explorer.exe'
            - '\lsass.exe'
    filter:
        SourceImage|startswith: 'C:\Windows\System32\'
    condition: selection and not filter
level: critical