Windows Win32 Security API

The Windows Win32 Security API provides a comprehensive set of functions for managing security and access control within the Windows operating system. This includes managing user accounts, groups, access tokens, security descriptors, and auditing.

Core Security Concepts

Understanding key security concepts is crucial when working with the Win32 Security API:

Access Tokens: Represent the security context of a process or thread, containing information about the user, privileges, and group memberships.
Security Descriptors: Objects that contain the security information of a securable object (e.g., files, registry keys, processes), including the owner, group, Discretionary Access Control List (DACL), and System Access Control List (SACL).
Access Control Lists (ACLs): A list of Access Control Entries (ACEs) that define the permissions granted or denied to specific security principals.
Privileges: Special rights assigned to user accounts that allow them to perform specific system-level operations.

Key Security Functions

OpenProcessToken
Opens the access token associated with a process. This is often the first step to querying or modifying the security context of a process.
```
BOOL OpenProcessToken(
  HANDLE  ProcessHandle,
  DWORD   DesiredAccess,
  PHANDLE TokenHandle
);
                    
```
- ProcessHandle: Handle to the process whose access token is to be opened.
- DesiredAccess: Access rights to the access token.
- TokenHandle: Pointer to a variable that receives the handle to the newly opened access token.

CreateFile (with Security Attributes)

Creates or opens a file or I/O device. When used with the `lpSecurityAttributes` parameter, it allows for the specification of a custom security descriptor for the created file.

HANDLE CreateFile(
  LPCSTR                lpFileName,
  DWORD                 dwDesiredAccess,
  DWORD                 dwShareMode,
  LPSECURITY_ATTRIBUTES lpSecurityAttributes,
  DWORD                 dwCreationDisposition,
  DWORD                 dwFlagsAndAttributes,
  HANDLE                hTemplateFile
);

lpSecurityAttributes: Pointer to a SECURITY_ATTRIBUTES structure that specifies the security attributes of the file.

SetSecurityInfo
Sets the security of an unprotected object, including server-based accounts, services, files, registry keys, and other securable objects.
```
DWORD SetSecurityInfo(
  SE_OBJECT_TYPE        ObjectType,
  LPCWSTR               pObjectName,
  SECURITY_INFORMATION  SecurityInfo,
  PSID                  psidOwner,
  PSID                  psidGroup,
  PACL                  pDacl,
  PACL                  pSacl
);
                    
```
- ObjectType: Type of the object.
- pObjectName: Pointer to the null-terminated string that names the object.
- SecurityInfo: Bitmap indicating the type of security information being set.
- psidOwner: Pointer to the owner identifier.
- psidGroup: Pointer to the primary group identifier.
- pDacl: Pointer to the DACL.
- pSacl: Pointer to the SACL.
GetAce
Retrieves a pointer to an access control entry (ACE) in an access control list (ACL).
```
BOOL GetAce(
  PACL  pAcl,
  DWORD dwIndex,
  LPVOID *pAce
);
                    
```
- pAcl: Pointer to an ACL.
- dwIndex: Index of the ACE to retrieve.
- pAce: Pointer to a pointer to an ACE structure.

Learn More

For in-depth documentation and advanced topics, refer to the official Microsoft documentation:

Microsoft Docs: Authorization Functions

Microsoft Docs: Security Identifiers