↳ GitHub sourceAnalytics ruleMedium
Excessive NXDOMAIN DNS Queries (ASIM DNS Schema)
Description
'This creates an incident in the event a client generates excessive amounts of DNS queries for non-existent domains.
This analytic rule uses [ASIM](https://aka.ms/AboutASIM) and supports any built-in or custom source that supports the ASIM DNS schema'
- Rule type
- Scheduled
- Version
- 1.3.4
- Query frequency
- 1h
- Query period
- 1h
- 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 threshold = 200;
_Im_Dns(responsecodename='NXDOMAIN')
| where isnotempty(DnsResponseCodeName)
//| where DnsResponseCodeName =~ "NXDOMAIN"
| summarize count() by SrcIpAddr, bin(TimeGenerated,15m)
| where count_ > threshold
| join kind=inner (_Im_Dns(responsecodename='NXDOMAIN')
) on SrcIpAddr
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
9800e51↗- Source identifier
c3b11fb2-9201-4844-b7b9-6b7bf6d9b851
Additional source files 1
Detections/ASimDNS/imDns_ExcessiveNXDOMAINDNSQueries.yamlsource ↗GSTEP / CATALOG TRACKING
Added to catalog : 16 Sept 2026 · 05:49 UTC
Last change observed : 16 Sept 2026 · 05:49 UTC