📜Windows Objects

What is Windows Objects ?

1. Definition of a Windows Object:

1. A Windows Object is a kernel-managed data structure that encapsulates and provides controlled access to a system resource, such as a file, thread, process, or synchronization primitive, through the use of secure handles and reference counting.

2. These objects provide a standardized interface(Like programming Attributes and Functions) for applications and the operating system to interact with hardware and system resources securely and efficiently. Each object encapsulates the necessary information and mechanisms to manage and control access to the resource it represents.

3. Windows Object: This is a specific, active instance of that Object Type, created in memory when an application or the system requests it. For example, when you run a program, a Process Object (an instance of the Process Object Type) is created in memory to manage that program.

2. Components of a Windows Object

1. Object Header: Contains metadata about the object, including its type, name, reference count, and security descriptor.​

2. Object Body: Holds the data specific to the type of resource the object represents. For example, a file object would contain file-specific information, while a process object would contain process-specific data.​

3. Security Descriptor: Defines the access control policies, specifying which users or processes can interact with the object and what operations they can perform.​

4. Handle: A reference provided to user-mode applications, allowing them to perform operations on the object without direct access to the underlying resource.

3. Lifecycle and Management

Windows objects are managed by the Object Manager, a kernel component responsible for creating, maintaining, and deleting objects. When an application needs to use a resource, it requests the Object Manager to create or open the corresponding object, receiving a handle in return. The Object Manager ensures that resources are properly tracked and released when no longer in use, utilizing reference counting to determine when an object can be safely destroyed.

3. Examples of Windows Objects

• File Object: Represents an open file or I/O device.​

• Process Object: Represents an executing program.​

• Thread Object: Represents a single thread of execution within a process.​

• Event Object: Used for synchronization between threads or processes.​

• Semaphore Object: Controls access to a resource pool.​

• Registry Key Object: Represents a key in the Windows Registry.

4. What Does “Interface” Mean in Windows Objects?

In the context of Windows Objects, the word interface means:

A set of rules, functions, and structures provided by Windows that programs use to interact with system resources like files, processes, threads, and more.

5. Core Components of a Kernel Object

(A) Object Type (Template)

• Defines what the object is (a "File" or "Process").

• Includes:

  • Data structure (how it’s stored in memory)

  • Methods (operations allowed on it, like Open, Close, Read)

  • Default attributes (security settings, access rules)

(B) Object Instance (Actual Object)

• A single, running copy of an object type.

  • Example:

    • Object Type = "File"

    • Object Instance = C:\Users\Doc.txt (an actual open file)

(C) Object Attributes (Properties)

These define the current state of the object. Example for a Process Object:

Attribute	Description
Process ID (PID)	Unique identifier
Access Token	Security permissions
Parent Process	Which process created it
Memory Usage	How much RAM it’s using

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6. How Programs Interact with Kernel Objects

Since kernel objects belong to the OS, applications cannot access them directly. Instead:

1. A program requests an object (e.g., "Open notes.txt").

2. Windows creates/retrieves the object and gives back a HANDLE (a reference number of your Object).

3. The program uses the handle to call methods (e.g., ReadFile, TerminateProcess).

4. When done, the handle is closed (CloseHandle), freeing resources.

Simple Translation:

The interface is how your application talks to the object — it’s a middleman between your app and the system resource.

Your app never touches the object directly — instead, it uses the interface (through functions, handles, and APIs) to ask Windows to do things.

7. What is an Object Type in Windows?

An Object Type in Windows defines the kind of resource an object represents and the rules and behaviors associated with it.

Every kernel object in Windows is part of a specific type, and that type determines:

• What operations you can perform on it

• What functions work with it

• How it's created, tracked, and deleted

• What kind of data structure and behavior it has

• Think of it Like a Class (OOP Style)

  If you're familiar with Object-Oriented Programming:

  • The Object Type is like a class (File, Process,)

  • The Object is an instance of that class

• Why Object Types Matter ?

  • They allow Windows to organize and manage system resources safely and consistently.

  • They ensure that a function like ReadFile works only on File objects — and not, say, on a Process.

  • They make it easier to enforce security and access control, because each type defines what permissions are valid.

• Every Object Type in Windows is represented internally by a structure called : OBJECT_TYPE

  It includes pointers to functions and rules that apply to that type of object.

What is Next ??

Once You’ve Understood Objects, Then Move On To:

1. Object Handles & Handle Tables

2. Access Tokens & Security Descriptors

3. Object Namespace (exploring via tools like WinObj)

4. Synchronization Objects (Mutex, Event, Semaphore)

5. ALPC Ports (Advanced, for inter-process communication)