↳ GitHub sourceAnalytics ruleMedium
Detect port misuse by static threshold (ASIM Network Session schema)
Description
'This detection rule detects port usage above the configured threshold. The rule utilize [ASIM](https://aka.ms/AboutASIM) normalization, and is applied to any source which supports the ASIM Network Session schema. To tune the rule to your environment configure it using the 'NetworkSession_Monitor_Configuration' watchlist. This rule leverages log summaries generated by a Summary Rule or Summarized Playbook. If no such summaries are available, the rule falls back to direct analysis using ASIM function.'
- Rule type
- Scheduled
- Version
- 1.2.0
- Declared status
- Available
- Query frequency
- 20m
- Query period
- 60m
- 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 lookback = 20m;
let mapping = _GetWatchlist('NetworkSession_Monitor_Configuration')
| where Type == "Detection" and ThresholdType == "Static" and Severity != "Disabled"
| extend
Ports = split(Ports, ","),
App = split(App, ","),
Protocol = split(Protocol, ","),
Direction = split(Direction, ","),
Action = split(Action, ",")
| project
Ports,
App,
Protocol,
Direction,
Action,
Type,
ThresholdType,
Threshold,
Severity,
Tactic,
Name,
Description
| mv-expand Ports
| mv-expand App
| mv-expand Protocol
| mv-expand Direction
| mv-expand Action
| extend
Ports = tostring(Ports),
App = tostring(App),
Protocol = tostring(Protocol),
Direction = tostring(Direction),
Action = tostring(Action),
Threshold = toint(Threshold);
let NetworkSummary_Protocol = materialize(
union isfuzzy=true
(
NetworkSummary_Protocol_CL
| project v = int(2)
),
(
print int(1)
| project v = print_0
)
| summarize maxv = max(v)
| extend
NetworkSummary_Protocol_Exists = (maxv > 1),
NetworkCustomAnalyticsExists = false
);
let NetworkCustomAnalytics = materialize(
union isfuzzy=true
(
NetworkCustomAnalytics_protocol_CL
| project v = int(2)
),
(
print int(1)
| project v = print_0
)
| summarize maxv = max(v)
| extend
NetworkCustomAnalyticsExists = (maxv > 1),
NetworkSummary_Protocol_Exists = false
);
let allData = union isfuzzy=true
(
(datatable(
exists: int,
NetworkSummary_Protocol_Exists: bool,
NetworkCustomAnalyticsExists: bool
)[
1, false, false
]
| join (NetworkSummary_Protocol) on NetworkSummary_Protocol_Exists
| join (NetworkCustomAnalytics) on NetworkCustomAnalyticsExists
)
| join (
_Im_NetworkSession(starttime=bin(now(-20m), 20m), endtime=bin(now(), 20m))
| where TimeGenerated > bin(now(-20m), 20m)
| summarize Count=count()
by
NetworkProtocol,
DstPortNumber,
DstAppName,
NetworkDirection,
DvcAction,
bin(TimeGenerated, 20m)
| extend
EventTime = TimeGenerated,
Count = toint(Count),
DstPortNumber = toint(DstPortNumber),
exists=int(1)
)
on exists
| project-away exists*, maxv, NetworkSummary_Protocol_Exists*, NetworkCustomAnalyticsExists*
),
(
(datatable(exists: int, NetworkSummary_Protocol_Exists: bool)[1, false]
| join (NetworkSummary_Protocol) on NetworkSummary_Protocol_Exists
)
| join (
NetworkCustomAnalytics_protocol_CL
| where EventTime_t == toscalar(NetworkCustomAnalytics_protocol_CL
| summarize max(EventTime_t))
| project
NetworkProtocol=NetworkProtocol_s,
DstPortNumber=DstPortNumber_d,
DstAppName=DstAppName_s,
NetworkDirection=NetworkDirection_s,
DvcAction=DvcAction_s,
Count=count__d,
EventTime=EventTime_t,
TimeGenerated,
Type
| extend Count = toint(Count), DstPortNumber = toint(DstPortNumber), exists=int(1)
)
on exists
| project-away exists*, maxv, NetworkSummary_Protocol_Exists*, NetworkCustomAnalyticsExists*
),
(
NetworkSummary_Protocol_CL
| where EventTime == toscalar(NetworkSummary_Protocol_CL
| summarize max(EventTime))
| project
NetworkProtocol,
DstPortNumber,
DstAppName,
NetworkDirection,
DvcAction,
Count=count_,
EventTime,
TimeGenerated,
Type
| extend Count = toint(Count), DstPortNumber = toint(DstPortNumber)
)
| project-away exists*, maxv*, NetworkSummary_Protocol_Exists*, NetworkCustomAnalyticsExists*
;
allData
| where isnotempty(DstPortNumber)
| summarize Sum=sum(Count) by DstPortNumber, NetworkProtocol, NetworkDirection, DvcAction
| join kind=inner ['mapping'] where Ports has tostring(DstPortNumber)
| where Sum > Threshold
and (Protocol == "*" or Protocol has NetworkProtocol)
and (Direction == "*" or Direction has NetworkDirection)
and (Action == "*" or Action has DvcAction)
| project
Name,
Description,
NetworkProtocol,
DstPortNumber,
NetworkDirection,
DvcAction,
Severity,
Tactic
| summarize
NetworkProtocols=make_set_if(NetworkProtocol, isnotempty(NetworkProtocol), 20),
NetworkDirections=make_set_if(NetworkDirection, isnotempty(NetworkDirection), 5),
DvcActions=make_set_if(DvcAction, isnotempty(DvcAction), 10)
by Name, Severity, Tactic, DstPortNumber, Description
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
9800e51↗- Source identifier
156997bd-da0f-4729-b47a-0a3e02dd50c8
GSTEP / CATALOG TRACKING
Added to catalog : 16 Sept 2026 · 05:49 UTC
Last change observed : 16 Sept 2026 · 05:49 UTC