🧠 Windows Internals: The Cyber Defender's Deep Dive Into the KernelBy 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:

📌 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

📌 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:

cOpenProcess() → 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:

💣 Tactics & Techniques Based on Internals

🔮 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.