MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Initial Access | T1078 Valid Accounts, T1133 External Remote Services |
Rule body kusto
id: 40a98355-0e52-479f-8c91-4ab659cba878
name: Zscaler - Shared ZPA session
description: |
'Detects shared ZPA session.'
severity: High
status: Available
requiredDataConnectors:
- connectorId: CustomLogsAma
datatypes:
- ZPA_CL
queryFrequency: 1h
queryPeriod: 24h
triggerOperator: gt
triggerThreshold: 0
tactics:
- InitialAccess
relevantTechniques:
- T1078
- T1133
query: |
let open_sessions =
ZPAEvent
| where DvcAction == 'open'
| summarize timestampstart = min(TimeGenerated) by DstUserName, SrcIpAddr, NetworkSessionId
| sort by timestampstart asc;
let closed_sessions =
ZPAEvent
| where TimeGenerated > ago(1h)
| where DvcAction == 'close'
| summarize timestampend = max(TimeGenerated) by DstUserName, SrcIpAddr, NetworkSessionId
| sort by timestampend asc;
open_sessions
| join (closed_sessions) on DstUserName
| sort by DstUserName, timestampstart
| extend prev_session_closetime = prev(timestampend,1)
| extend prev_session_starttime = prev(timestampstart,1)
| extend PreviousSrcIpAddr = prev(SrcIpAddr, 1)
| extend prev_sessionuser = prev(DstUserName, 1)
| where DstUserName == prev_sessionuser
| where SrcIpAddr != PreviousSrcIpAddr
| where prev_session_closetime > timestampstart
| project DstUserName, SrcIpAddr, PreviousSrcIpAddr
| extend IPCustomEntity = SrcIpAddr, AccountCustomEntity = DstUserName
entityMappings:
- entityType: Account
fieldMappings:
- identifier: Name
columnName: AccountCustomEntity
- entityType: IP
fieldMappings:
- identifier: Address
columnName: IPCustomEntity
version: 1.0.2
kind: Scheduled
Stages and Predicates
Let binding: closed_sessions
let closed_sessions = ZPAEvent
| where TimeGenerated > ago(1h)
| where DvcAction == 'close'
| summarize timestampend = max(TimeGenerated) by DstUserName, SrcIpAddr, NetworkSessionId
| sort by timestampend asc;
The stages below define let open_sessions (the rule's main pipeline source).
Stage 1: source
ZPAEvent
Stage 2: where
| where DvcAction == 'open'
Stage 3: summarize
| summarize timestampstart = min(TimeGenerated) by DstUserName, SrcIpAddr, NetworkSessionId
Stage 4: sort
| sort by timestampstart asc
The stages below run on open_sessions (the outer pipeline).
Stage 5: join
open_sessions
| join (closed_sessions) on DstUserName
Stage 6: sort
| sort by DstUserName, timestampstart
Stage 7: extend (4 consecutive steps)
| extend prev_session_closetime = prev(timestampend,1)
| extend prev_session_starttime = prev(timestampstart,1)
| extend PreviousSrcIpAddr = prev(SrcIpAddr, 1)
| extend prev_sessionuser = prev(DstUserName, 1)
Stage 8: where
| where DstUserName == prev_sessionuser
Stage 9: where
| where SrcIpAddr != PreviousSrcIpAddr
Stage 10: where
| where prev_session_closetime > timestampstart
Stage 11: project
| project DstUserName, SrcIpAddr, PreviousSrcIpAddr
Stage 12: extend
| extend IPCustomEntity = SrcIpAddr, AccountCustomEntity = DstUserName
Indicators
Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.
| Field | Kind | Values |
|---|---|---|
DstUserName | eq |
|
DvcAction | eq |
|
SrcIpAddr | ne |
|
prev_session_closetime | gt |
|
Output fields
Fields the rule emits when it matches. Chronicle authors list these in the outcome block; they appear on the detection and $risk_score drives alerting. Sentinel / Defender XDR rules build them up through project / summarize / extend stages. Sentinel maps these into alert fields via entityMappings and customDetails; Defender XDR custom detections surface them as alert fields directly.
| Field | Source |
|---|---|
DstUserName | project |
PreviousSrcIpAddr | project |
SrcIpAddr | project |
AccountCustomEntity | extend |
IPCustomEntity | extend |