Description: Malicious actors may add a value to the ‘sIDHistory’ attribute of a user object they control to establish persistence. “%%1793” occurs when SidHistory value is cleared
References: 1, 2, 3
SPL:
index="windows" source="XmlWinEventLog:Security" EventCode IN (4742, 4738) NOT SidHistory IN ("%%1793", "-")
| rename signature AS EventDescription, dest_nt_domain AS Domain
| eval Time=strftime(_time, "%Y-%m-%d %H:%M:%S %z")
| lookup ad_users sAMAccountName AS user OUTPUT displayName AS Name, description AS AccountDescription
| lookup ad_users sAMAccountName AS src_user OUTPUT displayName AS Admin_name
| eval Admin=src_user
| table Time, index, host, Domain, user, EventCode, EventDescription, Name, AccountDescription, Admin, Admin_name, SidHistory