Multiple users logged into a single machine at the same time, or even within the same hour, do not typically occur in networks we have observed.

ATT&CK Detection

Technique Tactic Level of Coverage
Valid Accounts Lateral Movement Moderate

Pseudocode

users_list = search UserSession:Login
users_grouped = group users_list by hostname
users_grouped = from users_grouped select min(time) as earliest_time, max(time) as latest_time count(user) as user_count 
multiple_logins = filter users_grouped where (latest_time - earliest_time <= 1 hour and user_count > 1)
output multiple_logins

Additional Notes:

Logon events are Windows Event Code 4624 for Windows Vista and above, 518 for pre-Vista. Logoff events are 4634 for Windows Vista and above, 538 for pre-Vista. Logon types 2, 3, 9 and 10 are of interest. For more details see the Logon Types table on Microsoft’s Audit Logon Events page.

Data Model References

Object Action Field
user_session login user
user_session login hostname