Managed Sentinel – Alert 030

Alert IDMS-A030
Alert NameExcessive outbound DNS queries
DescriptionThis is an outlier type of alert, which will alert when an internal machine generates a large volume of DNS queries towards an untrusted zone.
Customer to provide thresholds based on specifics to local environment.
Severity LevelLow
Threat IndicatorImproper Usage
MITRE ATT&CK TacticsPersistence
Defense Evasion
Exfiltration
Log sourcesFirewall Traffic Logs
False PositivesValid software, which uses DNS for transferring data
RecommendationsReview internal system and identify any suspicious applications or processes running on it. Perform a full AV/AM scan on the targeted machine.
For organizations, that use internal DNS servers, perimeter firewall will detect the spike being initiated from the internal DNS server. Additional review of the DNS servers events may be required to identified the source machine generating the high volume of DNS traffic.