4715(S): The audit policy (SACL) on an object was changed.

Subcategory: Audit Policy Change

Event Description:

This event generates every time local audit policy security descriptor changes.

This event is always logged regardless of the "Audit Policy Change" sub-category setting.

Note  For recommendations, see Security Monitoring Recommendations for this event.

Event XML:

- <Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">
- <System>
 <Provider Name="Microsoft-Windows-Security-Auditing" Guid="{54849625-5478-4994-A5BA-3E3B0328C30D}" /> 
 <EventID>4715</EventID> 
 <Version>0</Version> 
 <Level>0</Level> 
 <Task>13568</Task> 
 <Opcode>0</Opcode> 
 <Keywords>0x8020000000000000</Keywords> 
 <TimeCreated SystemTime="2015-09-30T19:59:39.964601800Z" /> 
 <EventRecordID>1049425</EventRecordID> 
 <Correlation /> 
 <Execution ProcessID="516" ThreadID="4668" /> 
 <Channel>Security</Channel> 
 <Computer>DC01.contoso.local</Computer> 
 <Security /> 
 </System>
- <EventData>
 <Data Name="SubjectUserSid">S-1-5-21-3457937927-2839227994-823803824-1104</Data> 
 <Data Name="SubjectUserName">dadmin</Data> 
 <Data Name="SubjectDomainName">CONTOSO</Data> 
 <Data Name="SubjectLogonId">0x11ae30</Data> 
 <Data Name="OldSd">D:(A;;DCSWRPDTRC;;;BA)(D;;DCSWRPDTRC;;;SY)S:NO\_ACCESS\_CONTROL</Data> 
 <Data Name="NewSd">D:(A;;DCSWRPDTRC;;;BA)(A;;DCSWRPDTRC;;;SY)S:NO\_ACCESS\_CONTROL</Data> 
 </EventData>
 </Event>

Required Server Roles: None.

Minimum OS Version: Windows Server 2008, Windows Vista.

Event Versions: 0.

Field Descriptions:

Subject:

• Security ID [Type = SID]: SID of account that requested the “change local audit policy security descriptor (SACL)” operation. Event Viewer automatically tries to resolve SIDs and show the account name. If the SID cannot be resolved, you will see the source data in the event.

Note  A security identifier (SID) is a unique value of variable length used to identify a trustee (security principal). Each account has a unique SID that is issued by an authority, such as an Active Directory domain controller, and stored in a security database. Each time a user logs on, the system retrieves the SID for that user from the database and places it in the access token for that user. The system uses the SID in the access token to identify the user in all subsequent interactions with Windows security. When a SID has been used as the unique identifier for a user or group, it cannot ever be used again to identify another user or group. For more information about SIDs, see Security identifiers.

• Account Name [Type = UnicodeString]: the name of the account that requested the “change local audit policy security descriptor (SACL)” operation.

• Account Domain [Type = UnicodeString]: subject’s domain or computer name. Formats vary, and include the following:

  • Domain NETBIOS name example: CONTOSO

  • Lowercase full domain name: contoso.local

  • Uppercase full domain name: CONTOSO.LOCAL

  • For some well-known security principals, such as LOCAL SERVICE or ANONYMOUS LOGON, the value of this field is “NT AUTHORITY”.

  • For local user accounts, this field will contain the name of the computer or device that this account belongs to, for example: “Win81”.

• Logon ID [Type = HexInt64]: hexadecimal value that can help you correlate this event with recent events that might contain the same Logon ID, for example, “4624: An account was successfully logged on.”

Audit Policy Change:

• Original Security Descriptor [Type = UnicodeString]: the old Security Descriptor Definition Language (SDDL) value for the audit policy.

• New Security Descriptor [Type = UnicodeString]: new Security Descriptor Definition Language (SDDL) value for the audit policy.

Note  The Security Descriptor Definition Language (SDDL) defines string elements for enumerating information contained in the security descriptor.

Example:

O:BAG:SYD:(D;;0xf0007;;;AN)(D;;0xf0007;;;BG)(A;;0xf0007;;;SY)(A;;0×7;;;BA)S:ARAI(AU;SAFA;DCLCRPCRSDWDWO;;;WD)

• O: = Owner. SID of specific security principal, or reserved (pre-defined) value, for example: BA (BUILTIN_ADMINISTRATORS), WD (Everyone), SY (LOCAL_SYSTEM), etc. See the list of possible values in the table below:

• G: = Primary Group.
• D: = DACL Entries.
• S: = SACL Entries.

DACL/SACL entry format: entry_type:inheritance_flags(ace_type;ace_flags;rights;object_guid;inherit_object_guid;account_sid)

Example: D:(A;;FA;;;WD)

• entry_type:

“D” - DACL

“S” - SACL

• inheritance_flags:

"P” - SDDL_PROTECTED, Inheritance from containers that are higher in the folder hierarchy are blocked.

"AI" - SDDL_AUTO_INHERITED, Inheritance is allowed, assuming that "P" Is not also set.

"AR" - SDDL_AUTO_INHERIT_REQ, Child objects inherit permissions from this object.

• ace_type:

"A" - ACCESS ALLOWED

"D" - ACCESS DENIED

"OA" - OBJECT ACCESS ALLOWED: only applies to a subset of the object(s).

"OD" - OBJECT ACCESS DENIED: only applies to a subset of the object(s).

"AU" - SYSTEM AUDIT

"A" - SYSTEM ALARM

"OU" - OBJECT SYSTEM AUDIT

"OL" - OBJECT SYSTEM ALARM

• ace_flags:

"CI" - CONTAINER INHERIT: Child objects that are containers, such as directories, inherit the ACE as an explicit ACE.

"OI" - OBJECT INHERIT: Child objects that are not containers inherit the ACE as an explicit ACE.

"NP" - NO PROPAGATE: only immediate children inherit this ace.

"IO" - INHERITANCE ONLY: ace doesn’t apply to this object, but may affect children via inheritance.

"ID" - ACE IS INHERITED

"SA" - SUCCESSFUL ACCESS AUDIT

"FA" - FAILED ACCESS AUDIT

• rights: A hexadecimal string which denotes the access mask or reserved value, for example: FA (File All Access), FX (File Execute), FW (File Write), etc.

• object_guid: N/A
• inherit_object_guid: N/A
• account_sid: SID of specific security principal, or reserved value, for example: AN (Anonymous), WD (Everyone), SY (LOCAL_SYSTEM), etc. See the table above for more details.

For more information about SDDL syntax, see these articles: https://msdn.microsoft.com/library/cc230374.aspx, https://msdn.microsoft.com/library/windows/hardware/aa374892(v=vs.85).aspx.

Security Monitoring Recommendations

For 4715(S): The audit policy (SACL) on an object was changed.

• Monitor for all events of this type, especially on high value assets or computers, because any change of the local audit policy security descriptor should be planned. If this action was not planned, investigate the reason for the change.