PH_RULE_WinDNSServer_SuspDNSTrafficResolved
Enabled
This rule detects that the response from DNS server to original DNS client, the destination IP is the originating client that made the DNS resolution request.
9
Security
Behavioral Anomaly
No Technique Specified
Network
Windows DNS (with debug log enabled) via FortiSIEM Agent
Correlation
Confirm if the lookup is intended or not. Determine application or business use of the domain, and block if necessary. info and some other TLDs are uncommon in business cases, and should be looked at with caution.
If the following pattern or patterns match an ingested event within the given time window in seconds, trigger an incident.
300 seconds
If the following defined pattern/s occur within a 300 second time window.
suspicious_dns
This is the named definition of the event query, this is important if multiple subpatterns are defined to distinguish them.
This is the query logic that matches incoming events
eventType CONTAIN "AO-WUA-DNS" AND eventAction = 0 AND type = "Response" AND direction = "Snd" AND ( dnsQueryName REGEXP "^.*\.info$" OR dnsQueryName IN (Group@PH_SYS_FORTIGUARD_MAL_DOMAIN) )
This defines how matching events are aggregated, only events with the same matching attribute values are grouped into one unique incident ID
destIpAddr,dnsQueryName
This is most typically a numerical constraint that defines when the rule should trigger an incident
COUNT(*) >= 1
This section defines which fields in matching raw events should be mapped to the incident attributes in the resulting incident.
The available raw event attributes to map are limited to the group by attributes and the aggregate event constraint fields for each subpattern
destIpAddr=suspicious_dns.destIpAddr,
dnsQueryName=suspicious_dns.dnsQueryName