The GROUP_MEMBERSHIP structure identifies a group to which an account belongs. It is sent within the KERB_VALIDATION_INFO (section 2.5) structure.

The format of the GROUP_MEMBERSHIP structure is defined as follows:

 typedef struct _GROUP_MEMBERSHIP {
   ULONG RelativeId;
   ULONG Attributes;

RelativeId: A 32-bit unsigned integer that contains the RID of a particular group.

Attributes: A 32-bit unsigned integer value that contains the group membership attributes set for the RID contained in RelativeId. The possible values for the Attributes flags are identical to those specified in KERB_SID_AND_ATTRIBUTES (section 2.2.1).