Detection rules › Kusto
ClientDeniedAccess
'Creates an incident in the event a Client has an excessive amounts of denied access requests.'
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Credential Access |
Rule body
id: a9956d3a-07a9-44a6-a279-081a85020cae
name: ClientDeniedAccess
description: |
'Creates an incident in the event a Client has an excessive amounts of denied access requests.'
severity: Medium
requiredDataConnectors:
- connectorId: SyslogAma
datatypes:
- Syslog
queryFrequency: 1h
queryPeriod: 1h
triggerOperator: gt
triggerThreshold: 0
tactics:
- CredentialAccess
relevantTechniques:
- T1110
query: |
let threshold = 15;
let rejectedAccess = SymantecVIP
| where isnotempty(RADIUSAuth)
| where RADIUSAuth =~ "Reject"
| summarize Total = count() by ClientIP, bin(TimeGenerated, 15m)
| where Total > threshold
| project ClientIP;
SymantecVIP
| where isnotempty(RADIUSAuth)
| where RADIUSAuth =~ "Reject"
| join kind=inner rejectedAccess on ClientIP
| summarize StartTime = min(TimeGenerated), EndTime = max(TimeGenerated), count() by ClientIP, User
entityMappings:
- entityType: Account
fieldMappings:
- identifier: FullName
columnName: User
- entityType: IP
fieldMappings:
- identifier: Address
columnName: ClientIP
version: 1.0.4
status: Available
kind: Scheduled
Stages and Predicates
Stage 0: let
let threshold = 15;
let rejectedAccess = SymantecVIP
| where isnotempty(RADIUSAuth)
| where RADIUSAuth =~ "Reject"
| summarize Total = count() by ClientIP, bin(TimeGenerated, 15m)
| where Total > threshold
| project ClientIP;
Stage 1: source
SymantecVIP
Stage 2: where
| where isnotempty(RADIUSAuth)
Stage 3: where
| where RADIUSAuth =~ "Reject"
Stage 4: join
| join kind=inner rejectedAccess on ClientIP
Stage 5: summarize
summarize EndTime, StartTime by ClientIP, User
Indicators
These rows show field, operator, and value matches.
| Field | Kind | Values | Search |
|---|---|---|---|
RADIUSAuth | eq |
| field:"RADIUSAuth" kind:eq value:"Reject" |
RADIUSAuth | is_not_null | field:"RADIUSAuth" kind:is_not_null | |
Total | gt |
| field:"Total" kind:gt value:"15" |
Output fields
These fields are emitted when the rule matches.
| Field | Source |
|---|---|
ClientIP | summarize |
EndTime | summarize |
StartTime | summarize |
User | summarize |