diff --git a/reactos/dll/win32/advapi32/sec/sid.c b/reactos/dll/win32/advapi32/sec/sid.c
index 20a904e63e6..91b8526512f 100644
--- a/reactos/dll/win32/advapi32/sec/sid.c
+++ b/reactos/dll/win32/advapi32/sec/sid.c
@@ -108,6 +108,10 @@ static const WELLKNOWNSID WellKnownSids[] =
     { {0,0}, WinBuiltinAuthorizationAccessSid, { SID_REVISION, 2, { SECURITY_NT_AUTHORITY }, { SECURITY_BUILTIN_DOMAIN_RID, DOMAIN_ALIAS_RID_AUTHORIZATIONACCESS } } },
     { {0,0}, WinBuiltinTerminalServerLicenseServersSid, { SID_REVISION, 2, { SECURITY_NT_AUTHORITY }, { SECURITY_BUILTIN_DOMAIN_RID, DOMAIN_ALIAS_RID_TS_LICENSE_SERVERS } } },
     { {0,0}, WinBuiltinDCOMUsersSid, { SID_REVISION, 2, { SECURITY_NT_AUTHORITY }, { SECURITY_BUILTIN_DOMAIN_RID, DOMAIN_ALIAS_RID_DCOM_USERS } } },
+    { {'L','W'}, WinLowLabelSid, { SID_REVISION, 1, { SECURITY_MANDATORY_LABEL_AUTHORITY}, { SECURITY_MANDATORY_LOW_RID} } },
+    { {'M','E'}, WinMediumLabelSid, { SID_REVISION, 1, { SECURITY_MANDATORY_LABEL_AUTHORITY}, { SECURITY_MANDATORY_MEDIUM_RID } } },
+    { {'H','I'}, WinHighLabelSid, { SID_REVISION, 1, { SECURITY_MANDATORY_LABEL_AUTHORITY}, { SECURITY_MANDATORY_HIGH_RID } } },
+    { {'S','I'}, WinSystemLabelSid, { SID_REVISION, 1, { SECURITY_MANDATORY_LABEL_AUTHORITY}, { SECURITY_MANDATORY_SYSTEM_RID } } },
 };
 
 typedef struct WELLKNOWNRID
diff --git a/reactos/include/psdk/winnt.h b/reactos/include/psdk/winnt.h
index dec430e0142..8cd50947e28 100644
--- a/reactos/include/psdk/winnt.h
+++ b/reactos/include/psdk/winnt.h
@@ -596,6 +596,14 @@ typedef DWORD FLONG;
 #define DOMAIN_GROUP_RID_ENTERPRISE_ADMINS      0x00000207L
 #define DOMAIN_GROUP_RID_POLICY_ADMINS          0x00000208L
 
+#define SECURITY_MANDATORY_LABEL_AUTHORITY {0,0,0,0,0,16}
+#define SECURITY_MANDATORY_UNTRUSTED_RID        0x00000000L
+#define SECURITY_MANDATORY_LOW_RID              0x00001000L
+#define SECURITY_MANDATORY_MEDIUM_RID           0x00002000L
+#define SECURITY_MANDATORY_HIGH_RID             0x00003000L
+#define SECURITY_MANDATORY_SYSTEM_RID           0x00004000L
+#define SECURITY_MANDATORY_PROTECTED_PROCESS_RID 0x00005000L
+
 #define DOMAIN_ALIAS_RID_ADMINS                 0x00000220L
 #define DOMAIN_ALIAS_RID_USERS                  0x00000221L
 #define DOMAIN_ALIAS_RID_GUESTS                 0x00000222L
@@ -621,70 +629,84 @@ typedef DWORD FLONG;
 
 #define SECURITY_MANDATORY_LABEL_AUTHORITY  {0,0,0,0,0,16}
 
-typedef enum
-{
-    WinNullSid = 0,
-    WinWorldSid,
-    WinLocalSid,
-    WinCreatorOwnerSid,
-    WinCreatorGroupSid,
-    WinCreatorOwnerServerSid,
-    WinCreatorGroupServerSid,
-    WinNtAuthoritySid,
-    WinDialupSid,
-    WinNetworkSid,
-    WinBatchSid,
-    WinInteractiveSid,
-    WinServiceSid,
-    WinAnonymousSid,
-    WinProxySid,
-    WinEnterpriseControllersSid,
-    WinSelfSid,
-    WinAuthenticatedUserSid,
-    WinRestrictedCodeSid,
-    WinTerminalServerSid,
-    WinRemoteLogonIdSid,
-    WinLogonIdsSid,
-    WinLocalSystemSid,
-    WinLocalServiceSid,
-    WinNetworkServiceSid,
-    WinBuiltinDomainSid,
-    WinBuiltinAdministratorsSid,
-    WinBuiltinUsersSid,
-    WinBuiltinGuestsSid,
-    WinBuiltinPowerUsersSid,
-    WinBuiltinAccountOperatorsSid,
-    WinBuiltinSystemOperatorsSid,
-    WinBuiltinPrintOperatorsSid,
-    WinBuiltinBackupOperatorsSid,
-    WinBuiltinReplicatorSid,
-    WinBuiltinPreWindows2000CompatibleAccessSid,
-    WinBuiltinRemoteDesktopUsersSid,
-    WinBuiltinNetworkConfigurationOperatorsSid,
-    WinAccountAdministratorSid,
-    WinAccountGuestSid,
-    WinAccountKrbtgtSid,
-    WinAccountDomainAdminsSid,
-    WinAccountDomainUsersSid,
-    WinAccountDomainGuestsSid,
-    WinAccountComputersSid,
-    WinAccountControllersSid,
-    WinAccountCertAdminsSid,
-    WinAccountSchemaAdminsSid,
-    WinAccountEnterpriseAdminsSid,
-    WinAccountPolicyAdminsSid,
-    WinAccountRasAndIasServersSid,
-    WinNTLMAuthenticationSid,
-    WinDigestAuthenticationSid,
-    WinSChannelAuthenticationSid,
-    WinThisOrganizationSid,
-    WinOtherOrganizationSid,
-    WinBuiltinIncomingForestTrustBuildersSid,
-    WinBuiltinPerfMonitoringUsersSid,
-    WinBuiltinPerfLoggingUsersSid,
-    WinBuiltinAuthorizationAccessSid,
-    WinBuiltinTerminalServerLicenseServersSid,
-    WinBuiltinDCOMUsersSid
+typedef enum {
+    WinNullSid                                  = 0,
+    WinWorldSid                                 = 1,
+    WinLocalSid                                 = 2,
+    WinCreatorOwnerSid                          = 3,
+    WinCreatorGroupSid                          = 4,
+    WinCreatorOwnerServerSid                    = 5,
+    WinCreatorGroupServerSid                    = 6,
+    WinNtAuthoritySid                           = 7,
+    WinDialupSid                                = 8,
+    WinNetworkSid                               = 9,
+    WinBatchSid                                 = 10,
+    WinInteractiveSid                           = 11,
+    WinServiceSid                               = 12,
+    WinAnonymousSid                             = 13,
+    WinProxySid                                 = 14,
+    WinEnterpriseControllersSid                 = 15,
+    WinSelfSid                                  = 16,
+    WinAuthenticatedUserSid                     = 17,
+    WinRestrictedCodeSid                        = 18,
+    WinTerminalServerSid                        = 19,
+    WinRemoteLogonIdSid                         = 20,
+    WinLogonIdsSid                              = 21,
+    WinLocalSystemSid                           = 22,
+    WinLocalServiceSid                          = 23,
+    WinNetworkServiceSid                        = 24,
+    WinBuiltinDomainSid                         = 25,
+    WinBuiltinAdministratorsSid                 = 26,
+    WinBuiltinUsersSid                          = 27,
+    WinBuiltinGuestsSid                         = 28,
+    WinBuiltinPowerUsersSid                     = 29,
+    WinBuiltinAccountOperatorsSid               = 30,
+    WinBuiltinSystemOperatorsSid                = 31,
+    WinBuiltinPrintOperatorsSid                 = 32,
+    WinBuiltinBackupOperatorsSid                = 33,
+    WinBuiltinReplicatorSid                     = 34,
+    WinBuiltinPreWindows2000CompatibleAccessSid = 35,
+    WinBuiltinRemoteDesktopUsersSid             = 36,
+    WinBuiltinNetworkConfigurationOperatorsSid  = 37,
+    WinAccountAdministratorSid                  = 38,
+    WinAccountGuestSid                          = 39,
+    WinAccountKrbtgtSid                         = 40,
+    WinAccountDomainAdminsSid                   = 41,
+    WinAccountDomainUsersSid                    = 42,
+    WinAccountDomainGuestsSid                   = 43,
+    WinAccountComputersSid                      = 44,
+    WinAccountControllersSid                    = 45,
+    WinAccountCertAdminsSid                     = 46,
+    WinAccountSchemaAdminsSid                   = 47,
+    WinAccountEnterpriseAdminsSid               = 48,
+    WinAccountPolicyAdminsSid                   = 49,
+    WinAccountRasAndIasServersSid               = 50,
+    WinNTLMAuthenticationSid                    = 51,
+    WinDigestAuthenticationSid                  = 52,
+    WinSChannelAuthenticationSid                = 53,
+    WinThisOrganizationSid                      = 54,
+    WinOtherOrganizationSid                     = 55,
+    WinBuiltinIncomingForestTrustBuildersSid    = 56,
+    WinBuiltinPerfMonitoringUsersSid            = 57,
+    WinBuiltinPerfLoggingUsersSid               = 58,
+    WinBuiltinAuthorizationAccessSid            = 59,
+    WinBuiltinTerminalServerLicenseServersSid   = 60,
+    WinBuiltinDCOMUsersSid                      = 61,
+    WinBuiltinIUsersSid                         = 62,
+    WinIUserSid                                 = 63,
+    WinBuiltinCryptoOperatorsSid                = 64,
+    WinUntrustedLabelSid                        = 65,
+    WinLowLabelSid                              = 66,
+    WinMediumLabelSid                           = 67,
+    WinHighLabelSid                             = 68,
+    WinSystemLabelSid                           = 69,
+    WinWriteRestrictedCodeSid                   = 70,
+    WinCreatorOwnerRightsSid                    = 71,
+    WinCacheablePrincipalsGroupSid              = 72,
+    WinNonCacheablePrincipalsGroupSid           = 73,
+    WinEnterpriseReadonlyControllersSid         = 74,
+    WinAccountReadonlyControllersSid            = 75,
+    WinBuiltinEventLogReadersGroup              = 76
 } WELL_KNOWN_SID_TYPE;
 
 #define SE_CREATE_TOKEN_NAME	TEXT("SeCreateTokenPrivilege")