Detection rules › Kusto
Zscaler - Unexpected ZPA session duration
'Detects Unexpected ZPA session duration.'
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Initial Access |
Rule body
id: e07846e0-43ad-11ec-81d3-0242ac130003
name: Zscaler - Unexpected ZPA session duration
description: |
'Detects Unexpected ZPA session duration.'
severity: Medium
status: Available
requiredDataConnectors:
- connectorId: CustomLogsAma
datatypes:
- ZPA_CL
queryFrequency: 1h
queryPeriod: 24h
triggerOperator: gt
triggerThreshold: 0
tactics:
- InitialAccess
relevantTechniques:
- T1078
- T1133
query: |
let dt_lookBack = 24h;
let time_treshhold = timespan(08:00:00);
let open_sessions =
ZPAEvent
| where TimeGenerated > ago(dt_lookBack)
| where DvcAction == 'open'
| summarize timestampstart = min(TimeGenerated) by DstUserName, SrcIpAddr, ConnectionID
| sort by timestampstart asc;
let closed_sessions =
ZPAEvent
| where TimeGenerated > ago(dt_lookBack)
| where DvcAction == 'close'
| summarize timestampend = max(TimeGenerated) by DstUserName, SrcIpAddr, ConnectionID
| sort by timestampend asc;
open_sessions
| join (closed_sessions) on DstUserName, SrcIpAddr, ConnectionID
| extend duration = timestampend - timestampstart
| where duration > time_treshhold
| where DstUserName !has "ZPA LSS"
| sort by timestampstart asc
| extend IPCustomEntity = SrcIpAddr, AccountCustomEntity = DstUserName
entityMappings:
- entityType: Account
fieldMappings:
- identifier: Name
columnName: AccountCustomEntity
- entityType: IP
fieldMappings:
- identifier: Address
columnName: IPCustomEntity
version: 1.0.3
kind: Scheduled
Stages and Predicates
Stage 0: let
let dt_lookBack = 24h;
let time_treshhold = timespan(08:00:00);
let open_sessions = ZPAEvent <inlined as stages below>;
let closed_sessions =
ZPAEvent
| where TimeGenerated > ago(dt_lookBack)
| where DvcAction == 'close'
| summarize timestampend = max(TimeGenerated) by DstUserName, SrcIpAddr, ConnectionID
| sort by timestampend asc;
Stage 1: source
ZPAEvent
Stage 2: where
| where TimeGenerated > ago(dt_lookBack)
Stage 3: where
| where DvcAction == 'open'
Stage 4: summarize
| summarize timestampstart = min(TimeGenerated) by DstUserName, SrcIpAddr, ConnectionID
Stage 5: sort
| sort by timestampstart asc
Stage 6: join
| join (closed_sessions) on DstUserName, SrcIpAddr, ConnectionID
Stage 7: extend
extend duration
Stage 8: where
where duration > time_treshhold
Stage 9: where
where not (DstUserName contains "ZPA LSS")
Stage 10: sort
sort by timestampstart
Stage 11: extend
extend AccountCustomEntity, IPCustomEntity
Indicators
These rows show field, operator, and value matches.
| Field | Kind | Values | Search |
|---|---|---|---|
DvcAction | eq |
| field:"DvcAction" kind:eq |
duration | cross_field_compare |
| field:"duration" kind:cross_field_compare value:"time_treshhold" |
Exclusions
The rule actively suppresses these predicates.
| Field | Kind | Excluded values | Search |
|---|---|---|---|
DstUserName | match | ZPA LSS | excludes:DstUserName field:"DstUserName" value:"ZPA LSS" |
Output fields
These fields are emitted when the rule matches.
| Field | Source |
|---|---|
ConnectionID | summarize |
DstUserName | summarize |
SrcIpAddr | summarize |
timestampstart | summarize |
duration | extend |
AccountCustomEntity | extend |
IPCustomEntity | extend |