Recipe17.13.Obtaining SecurityAudit Information

Recipe 17.13. Obtaining Security/Audit Information

Problem

You need to obtain the security rights and/or audit information for a file or registry key.

Solution

When obtaining security/audit information for a file, use the static GetAccessControl method of the File class to obtain a System.Security.AccessControl.FileSecurity object. Use the FileSecurity object to access the security and audit information for the file. These steps are demonstrated in Example 17-15.

Example 17-15. Obtaining security audit information

 public static void ViewFileRights() {     // Get security information from a file.     string file = @"c:\FOO.TXT";      FileSecurity fileSec = File.GetAccessControl(file);      DisplayFileSecurityInfo(fileSec); } public static void DisplayFileSecurityInfo(FileSecurity fileSec) {     Console.WriteLine("GetSecurityDescriptorSddlForm: {0}",         fileSec.GetSecurityDescriptorSddlForm(AccessControlSections.All));     foreach (FileSystemAccessRule ace in             fileSec.GetAccessRules(true, true, typeof(NTAccount)))     {         Console.WriteLine("\tIdentityReference.Value: {0}",                           ace.IdentityReference.Value);         Console.WriteLine("\tAccessControlType: {0}", ace.AccessControlType);         Console.WriteLine("\tFileSystemRights: {0}", ace.FileSystemRights);         Console.WriteLine("\tInheritanceFlags: {0}", ace.InheritanceFlags);         Console.WriteLine("\tIsInherited: {0}", ace.IsInherited);         Console.WriteLine("\tPropagationFlags: {0}", ace.PropagationFlags);         Console.WriteLine("-----------------\r\n\r\n");     }     foreach (FileSystemAuditRule ace in             fileSec.GetAuditRules(true, true, typeof(NTAccount)))     {         Console.WriteLine("\tIdentityReference.Value: {0}",                           ace.IdentityReference.Value);         Console.WriteLine("\tAuditFlags: {0}", ace.AuditFlags);         Console.WriteLine("\tFileSystemRights: {0}", ace.FileSystemRights);         Console.WriteLine("\tInheritanceFlags: {0}", ace.InheritanceFlags);         Console.WriteLine("\tIsInherited: {0}", ace.IsInherited);         Console.WriteLine("\tPropagationFlags: {0}", ace.PropagationFlags);         Console.WriteLine("-----------------\r\n\r\n");     }     Console.WriteLine("GetGroup(typeof(NTAccount)).Value: {0}",                       fileSec.GetGroup(typeof(NTAccount)).Value);     Console.WriteLine("GetOwner(typeof(NTAccount)).Value: {0}",                       fileSec.GetOwner(typeof(NTAccount)).Value);     Console.WriteLine("---------------------------------------\r\n\r\n\r\n"); }

These methods produce the following output:

 GetSecurityDescriptorSddlForm: O:BAG:SYD:PAI(A;;FA;;;SY)(A;;FA;;;BA)     IdentityReference.Value: NT AUTHORITY\SYSTEM     AccessControlType: Allow     FileSystemRights: FullControl     InheritanceFlags: None     IsInherited: False     PropagationFlags: None -----------------     IdentityReference.Value: BUILTIN\Administrators     AccessControlType: Allow     FileSystemRights: FullControl     InheritanceFlags: None     IsInherited: False     PropagationFlags: None ----------------- GetGroup(typeof(NTAccount)).Value: NT AUTHORITY\SYSTEM GetOwner(typeof(NTAccount)).Value: BUILTIN\Administrators

When obtaining security/audit information for a registry key, use the GetAccess-Control instance method of the Microsoft.Win32.RegistryKey class to obtain a System. Security.AccessControl.RegistrySecurity object. Use the RegistrySecurity object to access the security and audit information for the registry key. These steps are demonstrated in Example 17-16.

Example 17-16. Getting security or audit information for a registry key

 public static void ViewRegKeyRights() {     // Get security information from a registry key.     using (RegistryKey regKey =         Registry.LocalMachine.OpenSubKey(@"SOFTWARE\MyCompany\MyApp"))     {         RegistrySecurity regSecurity = regKey.GetAccessControl();         DisplayRegKeySecurityInfo(regSecurity);     } } public static void DisplayRegKeySecurityInfo(RegistrySecurity regSec) {     Console.WriteLine("GetSecurityDescriptorSddlForm: {0}",         regSec.GetSecurityDescriptorSddlForm(AccessControlSections.All));     foreach (RegistryAccessRule ace in             regSec.GetAccessRules(true, true, typeof(NTAccount)))     {         Console.WriteLine("\tIdentityReference.Value: {0}",                           ace.IdentityReference.Value);         Console.WriteLine("\tAccessControlType: {0}", ace.AccessControlType);         Console.WriteLine("\tRegistryRights: {0}", ace.RegistryRights.ToString());         Console.WriteLine("\tInheritanceFlags: {0}", ace.InheritanceFlags);         Console.WriteLine("\tIsInherited: {0}", ace.IsInherited);         Console.WriteLine("\tPropagationFlags: {0}", ace.PropagationFlags);         Console.WriteLine("-----------------\r\n\r\n");     }     foreach (RegistryAuditRule ace in             regSec.GetAuditRules(true, true, typeof(NTAccount)))     {         Console.WriteLine("\tIdentityReference.Value: {0}",                           ace.IdentityReference.Value);         Console.WriteLine("\tAuditFlags: {0}", ace.AuditFlags);         Console.WriteLine("\tRegistryRights: {0}", ace.RegistryRights.ToString());         Console.WriteLine("\tInheritanceFlags: {0}", ace.InheritanceFlags);         Console.WriteLine("\tIsInherited: {0}", ace.IsInherited);         Console.WriteLine("\tPropagationFlags: {0}", ace.PropagationFlags);         Console.WriteLine("-----------------\r\n\r\n");     }     Console.WriteLine("GetGroup(typeof(NTAccount)).Value: {0}",                       regSec.GetGroup(typeof(NTAccount)).Value);     Console.WriteLine("GetOwner(typeof(NTAccount)).Value: {0}",                       regSec.GetOwner(typeof(NTAccount)).Value);     Console.WriteLine("---------------------------------------\r\n\r\n\r\n"); }

These methods produce the following output:

 GetSecurityDescriptorSddlForm: O:S-1-5-21-329068152-1383384898-682003330-1004G:S-1- 5-21-329068152-1383384898-682003330-513D: AI(A;ID;KR;;;BU)(A;CIIOID;GR;;;BU)(A;ID;KA;;;BA)(A;CIIOID;GA;;;BA)(A;ID;KA;;;SY)(A;CI IOID;GA;;;SY)(A;ID;KA;;;S-1-5-21-329068152-1383384898-682003330- 1004)(A;CIIOID;GA;;;CO)     IdentityReference.Value: BUILTIN\Users     AccessControlType: Allow     RegistryRights: ReadKey     InheritanceFlags: None     IsInherited: True     PropagationFlags: None -----------------     IdentityReference.Value: BUILTIN\Users     AccessControlType: Allow     RegistryRights: -2147483648     InheritanceFlags: ContainerInherit     IsInherited: True     PropagationFlags: InheritOnly -----------------     IdentityReference.Value: BUILTIN\Administrators     AccessControlType: Allow     RegistryRights: FullControl     InheritanceFlags: None     IsInherited: True     PropagationFlags: None -----------------     IdentityReference.Value: BUILTIN\Administrators     AccessControlType: Allow     RegistryRights: 268435456     InheritanceFlags: ContainerInherit     IsInherited: True     PropagationFlags: InheritOnly -----------------     IdentityReference.Value: NT AUTHORITY\SYSTEM     AccessControlType: Allow     RegistryRights: FullControl     InheritanceFlags: None     IsInherited: True     PropagationFlags: None -----------------     IdentityReference.Value: NT AUTHORITY\SYSTEM     AccessControlType: Allow     RegistryRights: 268435456     InheritanceFlags: ContainerInherit     IsInherited: True     PropagationFlags: InheritOnly -----------------     IdentityReference.Value: OPERATOR-C1EFE0\Admin     AccessControlType: Allow     RegistryRights: FullControl     InheritanceFlags: None     IsInherited: True     PropagationFlags: None -----------------     IdentityReference.Value: CREATOR OWNER     AccessControlType: Allow     RegistryRights: 268435456     InheritanceFlags: ContainerInherit     IsInherited: True     PropagationFlags: InheritOnly ----------------- GetGroup(typeof(NTAccount)).Value: OPERATOR-C1EFE0\None GetOwner(typeof(NTAccount)).Value: OPERATOR-C1EFE0\Admin ---------------------------------------

Discussion

The essential method that is used to obtain the security information for a file or registry key is the GetAccessControl method. When this method is called on the RegistryKey object, a RegistrySecurity object is returned. However, when this method is called on a File class, a FileSecurity object is returned. The RegistrySecurity and FileSecurity objects essentially represent a Discretionary Access Control List (DACL), which is what developers writing code in unmanaged languages such as C++ are used to working with.

The RegistrySecurity and FileSecurity objects each contains a list of security rules that has been applied to the system object that it represents. The RegistrySecurity object contains a list of RegistryAccessRule objects, and the FileSecurity object contains a list of FileSystemAccessRule objects. These rule objects are the equivalent of the Access Control Entries (ACE) that make up the list of security rules within a DACL.

System objects other than just the File class and RegistryKey object allow security privileges to be queried. Table 17-1 lists all the .NET Framework classes that return a security object type and what that type is. In addition, the rule-object type that is contained in the security object is also listed.

Table 17-1. List of all *Security and *AccessRule objects and the types to which they apply
Class	Object returned by the GetAccessControl method	Rule-object type contained within the security object
`Directory`	`DirectorySecurity`	`FileSystemAccessRule`
`DirectoryInfo`	`DirectorySecurity`	`FileSystemAccessRule`
`EventWaitHandle`	`EventWaitHandleSecurity`	`EventWaitHandleAccessRule`
`File`	`FileSecurity`	`FileSystemAccessRule`
`FileInfo`	`FileSecurity`	`FileSystemAccessRule`
`FileStream`	`FileSecurity`	`FileSystemAccessRule`
`Mutex`	`MutexSecurity`	`MutexAccessRule`
`RegistryKey`	`RegistrySecurity`	`RegistryAccessRule`
`Semaphore`	`SemaphoreSecurity`	`SemaphoreAccessRule`

The abstraction of a system object's DACL through the *Security objects and the abstraction of a DACL's ACE through the *AccessRule objects allows easy access to the security privileges of that system object. In previous versions of the .NET Framework, these DACLs and their ACEs would have been accessible only in unmanaged code. With the latest .NET Framework, you now have access to view and program these objects.