T1055 Microsoft Sentinel · KQL

Detect Process Injection in Microsoft Sentinel

Adversaries may inject code into processes in order to evade process-based defenses as well as possibly elevate privileges. Process injection is a method of executing arbitrary code in the address space of a separate live process. 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 process injection may also evade detection from security products since the execution is masked under a legitimate process. There are many different ways to inject code into a process, many of which abuse legitimate functionalities. These implementations exist for every major OS but are typically platform specific. More sophisticated samples may perform multiple process injections to segment modules and further evade detection, utilizing named pipes or other inter-process communication (IPC) mechanisms as a communication channel.

MITRE ATT&CK

Tactic
Defense Evasion Privilege Escalation
Technique
T1055 Process Injection
Canonical reference
https://attack.mitre.org/techniques/T1055/

KQL Detection Query

Microsoft Sentinel (KQL)
kusto
// Broad process injection detection via Sysmon CreateRemoteThread and ProcessAccess
let HighRiskTargets = dynamic(["lsass.exe", "csrss.exe", "winlogon.exe", "services.exe", "svchost.exe", "explorer.exe", "spoolsv.exe"]);
let TrustedSources = dynamic(["MsMpEng.exe", "csrss.exe", "services.exe", "svchost.exe", "lsass.exe", "wmiprvse.exe", "System"]);
// Detection 1: CreateRemoteThread into another process (Sysmon EID 8)
DeviceEvents
| where Timestamp > ago(24h)
| where ActionType == "CreateRemoteThreadApiCall"
| where InitiatingProcessFileName !in~ (TrustedSources)
| extend TargetIsHighRisk = FileName in~ (HighRiskTargets)
| project Timestamp, DeviceName, AccountName, InitiatingProcessFileName, InitiatingProcessCommandLine, FileName, ProcessCommandLine, TargetIsHighRisk
| sort by Timestamp desc
high severity medium confidence

Detects cross-process CreateRemoteThread API calls using MDE DeviceEvents, which is the primary telemetry for generic process injection. Filters out known trusted OS sources and highlights injection into high-risk system processes like lsass.exe, csrss.exe, and svchost.exe. This is a broad parent detection — sub-technique detections provide more specific coverage.

Data Sources

Process: Process AccessProcess: OS API ExecutionMicrosoft Defender for Endpoint

Required Tables

DeviceEvents

False Positives & Tuning

  • Endpoint protection products (CrowdStrike, SentinelOne, Carbon Black) injecting DLLs for hooking and monitoring
  • Application compatibility shims (apphelp.dll) that inject into processes for compatibility fixes
  • Accessibility tools (screen readers, magnifiers) that inject into processes to read UI state
  • Development tools and debuggers (Visual Studio, x64dbg, WinDbg) attaching to processes during debugging sessions
Download portable Sigma rule (.yml)

Other platforms for T1055


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.

  1. Test 1CreateRemoteThread DLL Injection via PowerShell

    Expected signal: Sysmon Event ID 1: Process Create for notepad.exe spawned by PowerShell. If using the full injection API chain, Sysmon Event ID 8 (CreateRemoteThread) and Event ID 10 (ProcessAccess) will fire for the cross-process interaction.

  2. Test 2Process Injection via Mavinject

    Expected signal: Sysmon Event ID 1: Process Create for mavinject.exe with /INJECTRUNNING argument. Sysmon Event ID 8: CreateRemoteThread from mavinject.exe to the target. Sysmon Event ID 7: ImageLoad of the injected DLL in the target process.

  3. Test 3Ptrace-based Process Injection on Linux

    Expected signal: auditd: PTRACE syscall logged with type=SYSCALL and a]0=PTRACE_ATTACH. Syslog may show process attachment events. /proc/[pid]/status will show TracerPid set to the strace PID.

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Get the full detection package for T1055 including response playbook, investigation guide, and atomic red team tests.

Response PlaybookInvestigation GuideHunting QueriesAtomic Red Team TestsTuning Guidance

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