Requêtes pour la table NetworkSessions

Pour plus d’informations sur l’utilisation de ces requêtes dans le Portail Azure, consultez le didacticiel Log Analytics. Pour l’API REST, consultez Requête.

Obtenir le trafic vers des ports non standard

Cette requête identifie les adresses IP sources qui envoient des demandes de connexion sur plusieurs ports. Il peut s’agir d’une indication des tentatives d’adversaire pour répertorier les services disponibles. Références : Analyse du service réseau MITRE (T1046)

// This query identifies source IP addresses sending connection requests over multiple ports.
// This could be an indication of adversary attempts to list available services.
// References: MITRE Network Service Scanning (T1046)
let threshold=5;
// Used to filter commonly used ports in your org
let commonPorts=dynamic([443, 53, 389, 80, 0, 880, 8888, 8080]);
NetworkSessions
 | where isnotempty(DstPortNumber) and not(ipv4_is_private(DstIpAddr) ) 
 // filter out IANA ephemeral or negotiated ports as per https://en.wikipedia.org/wiki/Ephemeral_port
 | where DstPortNumber !between (toint(49512) .. toint(65535)) 
     and DstPortNumber !in (commonPorts)
 | where EventResult == "Failure" 
 | summarize PortCount=dcount(DstPortNumber) by SrcIpAddr, bin(TimeGenerated, 2m)
 | where PortCount > threshold

Trafic en volume élevé vers des domaines rares

Cette requête identifie les domaines recevant une quantité rare de volume de données. Il peut s’agir d’une indication des tentatives d’adversaire pour voler et exfiltrer des données.

// This query identifies domains receiving uncommon about of data volume.
// This could be an indication of adversary attempts to steal and exfiltrate data.
let isInternal = (url_hostname:string){url_hostname endswith ".local" or url_hostname endswith ".lan" or url_hostname endswith ".home"};
    // used to exclude internal traffic
let top1M =  (externaldata (Position:int, Domain:string) [@"http://s3-us-west-1.amazonaws.com/umbrella-static/top-1m.csv.zip"]  with (format="csv", zipPattern="*.csv"));
    // fetch the alexa top 1M domains
let top2ndLevelDomain=top1M
    | extend Domain = tolower(extract("([^.]*).{0,7}$", 1, Domain)) 
    | distinct Domain;
let rareDomainTraffic = NetworkSessions
    | where isnotempty(UrlHostname) and not(isInternal(UrlHostname))
    | extend SndLevelDomain=tolower(extract("([^.]*).{0,7}$", 1, UrlHostname))
    | where SndLevelDomain !in (top2ndLevelDomain)
    | summarize BytesSent=sum(SrcBytes) by SndLevelDomain, UrlHostname;
rareDomainTraffic | summarize TotalBytes=sum(BytesSent) by SndLevelDomain
| join kind=innerunique
    rareDomainTraffic
        on SndLevelDomain
| sort by TotalBytes desc