Explanation:

For a near-real-time (NRT) analytics rule that detects sign-ins by a designated break-glass account, the most direct and performant pattern is to filter SigninLogs by joining to a Microsoft Sentinel watchlist that contains the protected account(s). Sentinel exposes watchlists to KQL through the helper function _GetWatc hlist( ' < watchlist-name > ' ) , which returns a table with standard columns (including SearchKey ) plus any custom columns you imported. Using join kind=inner ensures the result set includes only those SigninLogs rows whose UserPrincipalName matches an entry in the watchlist-ideal for alerting on a high-value account without post-filtering.
The completed query is:
SigninLogs | join kind=inner (_GetWatchlist( ' breakglass_account ' )) on $left.UserPrincipalName == $right.
SearchKey
This approach satisfies the requireme nt to implement an NRT rule for the break-glass account because:
* NRT rules support KQL with joins and watchlists and are optimized for rapid evaluation over fresh data.
* Using a watchlist lets SecOps adjust monitored accounts without editing the rule-minimi zing administrative effort and aligning with least-privilege operations (no extra permissions beyond watchlist management).
* The inner join pattern reduces noise by returning only matched events, which are then turned into alerts
/incidents by the NRT rule.
Thus, select join and GetWatchlist , and join UserPrincipalName to the watchlist's SearchKey .