↳ GitHub sourceAnalytics ruleMedium
A host is potentially running PowerShell to send HTTP(S) requests (ASIM Web Session schema)
Description
'This rule identifies a web request with a user agent header known to belong PowerShell. <br>You can add custom Powershell indicating User-Agent headers using a watchlist, for more information refer to the [UnusualUserAgents Watchlist](https://aka.ms/ASimUnusualUserAgentsWatchlist).<br><br>
This analytic rule uses [ASIM](https://aka.ms/AboutASIM) and supports any built-in or custom source that supports the ASIM WebSession schema (ASIM WebSession Schema)'
- Rule type
- Scheduled
- Version
- 1.1.5
- Query frequency
- 15m
- Query period
- 15m
- Trigger
- gt 0
Declared MITRE coverage
Declared sources
Metadata from the source file. No dependencies inferred from KQL.
Connectors
Data types
KQL query
Original query, unchanged.
let threatCategory="Powershell";
let knownUserAgentsIndicators = materialize(externaldata(UserAgent:string, Category:string)
[ @"https://raw.githubusercontent.com/Azure/Azure-Sentinel/master/Sample%20Data/Feeds/UnusualUserAgents.csv"]
with(format="csv", ignoreFirstRecord=True));
let knownUserAgents=toscalar(knownUserAgentsIndicators | where Category==threatCategory | where isnotempty(UserAgent) | summarize make_list(UserAgent));
let customUserAgents=toscalar(_GetWatchlist("UnusualUserAgents") | where SearchKey==threatCategory | extend UserAgent=column_ifexists("UserAgent","") | where isnotempty(UserAgent) | summarize make_list(UserAgent));
let fullUAList = array_concat(knownUserAgents,customUserAgents);
_Im_WebSession(httpuseragent_has_any=fullUAList)
| project SrcIpAddr, Url, TimeGenerated, HttpUserAgent, SrcUsername
| extend AccountName = tostring(split(SrcUsername, "@")[0]), AccountUPNSuffix = tostring(split(SrcUsername, "@")[1])
Declared entities
Related content
Links established from declared identifiers and solution manifests.
Source provenance
GitHubDisplayed values come from files in Azure/Azure-Sentinel. They describe the published template, not your workspace configuration.
- Commit
7ca9800↗- Source identifier
42436753-9944-4d70-801c-daaa4d19ddd2
Additional source files 1
Detections/ASimWebSession/UnusualUAPowershell.yamlsource ↗GSTEP / CATALOG TRACKING
Added to catalog : 16 Sept 2026 · 05:49 UTC
Last change observed : 16 Sept 2026 · 05:49 UTC