SPSite.LastSecurityModifiedDate Property

Gets the date and time in Coordinated Universal Time (UTC) when security on the site was last changed.

Namespace:  Microsoft.SharePoint
Assembly:  Microsoft.SharePoint (in Microsoft.SharePoint.dll)
Available in Sandboxed Solutions: Yes
Available in SharePoint Online

public DateTime LastSecurityModifiedDate { get; }

Property Value

Type: System.DateTime
A System.DateTime object that contains the date and time when the security was last changed.