Forum Discussion
Azure Sentinel rule to identify if user has not produced any events in 60 days
I am working on a rule that uses a watchlist of elevated accounts. What I am trying to create is a rule that will tell me if one of these elevated accounts has not been used in over 60 days so we can mark it for removal from the list. I am looking at the SecurityEvent table for any events these users generate. I can not seem to find a way to a "last event" type comparison. I can get a list of things they have done with starttime and endtime, but nothing I do seems to show a user that has not done any activity in 60 days or more. If anyone has done this, could you please share your rule/wisdom?
- Assuming you have just listed your userprincipalnames in your watchlist, and your on premise account is just part before the @ then these two should work. When joining you need to have a column that matches on both sides (your query and your watchlist). For signinlogs userprincipalname is fine because that's what Azure AD uses to identify people. We will just rename userprincipalname to username to match your watchlist. I added ResultType = 0 to only get successful signins, but you can remove if you want
let adminlist = (_GetWatchlist("Elevated_accounts")|project UserName);
SigninLogs
| where TimeGenerated > ago (30d)
| extend UserName = UserPrincipalName
| where UserName in (adminlist)
| where ResultType == 0
| distinct UserName
| join kind=rightanti adminlist on UserName
For SecurityEvent we want to use TargetUserName, so we will rename it when we set our variable and trim the @yourdomain.com part out
let adminlist = _GetWatchlist("Elevated_accounts")|extend TargetUserName = trim_end(@"@(.*)", UserName)|project TargetUserName;
SecurityEvent
| where TimeGenerated > ago(30d)
| where TargetUserName in (adminlist)
| distinct TargetUserName
| join kind = rightanti adminlist on TargetUserName
Try those and let me know
11 Replies
Marc_Jacquard I would use the SignInLogs to determine if the user has signed in during your time frame in question. You could use the UserPrincipalName or UserDisplayName fields to compare against your Watchlist.
- Gary, I tried that initially, but I wanted to see any activity. Below is my current logic. I just can not seem to get the time comparison correct. No matter which log source I use, I always have people who who have been active in the last 7 days even though I know some have not been. I switch between in~ and !in~ for testing. It appears I just do not have the time comparison logic correct.
let adminlist = (_GetWatchlist("Elevated_accounts")|project UserName);
let starttime = 31d;
//let midtime = 30d;
//let endtime =10m;
SecurityEvent
| where TimeGenerated > ago(32d)
|extend Account = trim_start(@"^.*\\", Account)
| where Account in~ (adminlist)
//|where EventID == "4624"
//|where Account !endswith "$"
| summarize StartTimeUtc = min(TimeGenerated), EndTimeUtc = max(TimeGenerated) by Account, EventID
//|where EndTimeUtc - StartTimeUtc > starttimeMarc_Jacquard I would recommend at least combining the two tables if you want to get the best picture of user activity. My admin account has logged into my Azure Sentinel instance quite a bit in the last week but has not performed any activity that would show up in SecurityEvent (which shows information from the Windows machines so I am not sure that is the correct table. AzureActivity may be better)
