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🧠 Windows Internals: The Cyber Defender's Deep Dive Into the Kernel By CyberDudeBivash — World’s Top Cybersecurity Researcher | Hacker | Founder of cyberdudebivash.com

 


🔍 Why Study Windows Internals?

Understanding Windows Internals isn’t optional anymore. It’s mandatory for:

  • Advanced malware reverse engineering

  • Kernel-level threat hunting

  • Privilege escalation in red team ops

  • Building evasive implants and detection-resistant payloads

The kernel is the battleground for stealthy attacks and defenders alike. If you're serious about dominating the cybersecurity battlefield, you must know how Windows works under the hood — from ring 0 to system calls to memory management.

🧱 Architecture Overview

Windows Operating System Stack:

sql
+-------------------------+
| User Applications       |   ← Ring 3 (User Mode)
+-------------------------+
| Win32 APIs              |
+-------------------------+
| NTDLL.DLL (Native API)  |
+-------------------------+
| Windows Kernel (ntoskrnl.exe) | ← Ring 0 (Kernel Mode)
+-------------------------+
| Hardware Abstraction Layer (HAL) |
+-------------------------+
| Physical Hardware       |
+-------------------------+

🧠 Core Kernel Components

1️⃣ NTOSKRNL.EXE

  • Master kernel image

  • Handles process/thread management, scheduling, I/O, memory

2️⃣ Executive

  • Higher-level services:

    • Object Manager

    • Memory Manager

    • Security Reference Monitor

    • I/O Manager

    • Process Manager

3️⃣ Kernel

  • Low-level scheduling, interrupt dispatching

4️⃣ HAL.DLL

  • Hardware Abstraction Layer

  • Converts hardware calls into OS-consumable interfaces

🧬 Processes, Threads, and Handles

🧩 Key Structures:

StructureDescription
EPROCESSRepresents a process
ETHREADThread-level metadata
KTHREADKernel-mode thread context
HANDLE_TABLEUser-mode handle translation

📌 Use in Cyber Attacks:

  • Malware may inject shellcode by walking the EPROCESS list

  • AVs often scan HANDLE_TABLES to detect suspicious object access

  • Red Teams abuse NtQuerySystemInformation to dump all EPROCESS blocks

📂 Registry Internals

  • Stored in Hives like SYSTEM, SOFTWARE, SAM

  • Backed by HKLM and HKCU

  • Lives in memory in CMHIVE, HHIVE, and other volatile structures

📌 Persistence Technique:

  • Add payload to HKLM\Software\Microsoft\Windows\CurrentVersion\Run

  • Use Image File Execution Options for debugger-based hijacking

🧱 Windows Security Architecture

ComponentDescription
LSASS.EXELocal Security Authority — handles credentials
SAMStores hashed passwords
SRM (Security Reference Monitor)Enforces ACLs and object security
WinlogonSession manager
Userinit, explorer.exeStartup programs for user sessions

📌 Credential Dumping Risk:

  • Attackers target LSASS for WDigest, Kerberos, MSV1_0 creds

  • Tools: Mimikatz, ProcDump, PPL Bypass, Handle Hijack

🧠 Memory Management Internals

🔢 Virtual Address Space:

  • User Mode: 0x00000000 to 0x7FFFFFFF

  • Kernel Mode: 0x80000000 to 0xFFFFFFFF

Key Concepts:

  • Paging: Backed by pagefile.sys

  • Working Sets: Processes’ active memory pages

  • Pool Memory:

    • NonPaged Pool: Critical kernel data

    • Paged Pool: Can be swapped

📌 Exploit Surface: Kernel pool overflows (like MS17-010/EternalBlue) rely on manipulating pool headers and metadata.

🔧 System Calls & API Layers

  • High-level Win32 → Native API (NTDLL.DLL) → Syscall to kernel

Example:

c
OpenProcess() → NtOpenProcess() → SYSENTER → Kernel

🛠️ Red Team Trick:

  • Use syswhispers to generate clean syscall stubs (bypass EDR hooked APIs)

🛡️ Driver Architecture

Drivers (*.sys files) are loaded into kernel space.

Types:

  • WDM: Traditional Windows Driver Model

  • KMDF: Kernel-Mode Driver Framework

  • Minifilter Drivers: Used by AVs/EDRs

📌 Persistence Tactic: Install a signed vulnerable driver to load malicious code (e.g., Capcom.sys, RTCore64.sys)

📊 Windows Logging & Forensics

📁 Event Logs:

  • Security.evtx

  • System.evtx

  • AppLocker, Sysmon, PowerShell Logs

🔍 Forensic Targets:

AreaWhat to Monitor
PrefetchApp execution timestamps
ShimcacheLast executed files
Amcache.hveBinary metadata
SRUMNetwork & app usage
WMI EventsScheduled or triggered payloads

💣 Tactics & Techniques Based on Internals

TacticExample
Privilege EscalationAbuse SeDebugPrivilege, token duplication
Process InjectionWriteProcessMemory + CreateRemoteThread
PPL BypassUnprotect LSASS for dumping
Direct SyscallsEvasion from NTDLL hooks
Driver ExploitsElevation via vulnerable .sys files

🔮 Windows Internals + AI + LLM = Cyber Arsenal

Modern attackers (including APTs) now blend:

  • LLMs to reverse engineer kernel functions

  • AI to automate syscall crafting and payload obfuscation

  • EDR bypassing using memory-level persistence from internal knowledge

Defenders must adapt with:

  • Kernel-level visibility (EDR, YARA on memory)

  • Syscall behavior monitoring

  • Windows Internals mastery

🧠 Conclusion

“You cannot protect or attack what you don’t understand. Windows Internals is the spellbook every cyber sorcerer must master.” — CyberDudeBivash

Whether you’re red teaming, blue teaming, or malware reversing — Windows Internals is your ultimate map to the kingdom.

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