Challenge

A host with SMB open on port 139.

Approach

Protocol and session details came back as SMB 3.1.1 with AES-128-GCM, and the auth domain was BSIDESRDU-FLAGS:

USER = BSIDESRDU-FLAGS
SMB 3.1.1
AES 128 GCM
Auth domain: BSIDESRDU-FLAGS179

Walking SIDs over the LSARPC pipe pulled the machine SID and a local account:

10.100.50.64:139 - PIPE(LSARPC) LOCAL(BSIDESRDU-FLAGS179 - 5-21-1393815661-1802593431-2363570036) DOMAIN(WORKGROUP - )
10.100.50.64:139 - USER=nobody RID=501

This is as far as the notes go. The enumeration is here but no flag was recorded.