Description
'Identifies clients with a high NXDomain count, which could be indicative of a DGA (cycling through possible C2 domains where most C2s are not live).
Alerts are generated when a new IP address is seen (based on not being associated with NXDomain records in the prior 10-day baseline period).'
- Type de règle
- Scheduled
- Version
- 1.0.3
- Statut déclaré
- Available
- Fréquence
- 1d
- Période analysée
- 10d
- Déclenchement
- gt 0
Couverture MITRE déclarée
Sources déclarées
Métadonnées du fichier source. Aucune dépendance déduite du KQL.
Connecteurs
Types de données
Requête KQL
Requête originale, sans modification.
let starttime = 10d;
let endtime = 1d;
let threshold = 100;
let nxDomainDnsEvents = DnsEvents
// ResultCode 3 => 'NXDOMAIN'
| where ResultCode == 3
| where QueryType in~ ("A", "AAAA")
| where ipv4_is_match("127.0.0.1", ClientIP) == False
| where Name !has "/"
| where Name has ".";
nxDomainDnsEvents
| where TimeGenerated > ago(endtime)
// sld = Second Level Domain
| extend sld = tostring(split(Name, ".")[-2])
| summarize StartTimeUtc = min(TimeGenerated), EndTimeUtc = max(TimeGenerated), dcount(sld), sampleNXDomainList=make_set(Name, 100) by ClientIP
| where dcount_sld > threshold
// Filter out previously seen IPs
// Returns all the records from the left side that don't have matches from the right
| join kind=leftanti (nxDomainDnsEvents
| where TimeGenerated between(ago(starttime)..ago(endtime))
| extend sld = tostring(split(Name, ".")[-2])
| summarize dcount(sld) by ClientIP, bin(TimeGenerated,1d)
| where dcount_sld > threshold
) on ClientIP
| order by dcount_sld desc
Entités déclarées
Contenus associés
Liens établis à partir des identifiants déclarés et des manifests des solutions.
Traçabilité de la source
GitHubLes valeurs affichées proviennent des fichiers du dépôt Azure/Azure-Sentinel. Elles décrivent le modèle publié, pas la configuration de votre workspace.
- Commit
9800e51↗- Identifiant source
a0907abe-6925-4d90-af2b-c7e89dc201a6
GSTEP / SUIVI DU CATALOGUE
Ajouté au catalogue : 16 sept. 2026 · 05:49 UTC
Dernier changement observé : 16 sept. 2026 · 05:49 UTC