Managed Sentinel – Alert 034

Alert IDMS-A034
Alert NameExcessive Outbound Firewall Allows (Cisco ASA Firewall)
DescriptionThis is an outlier type of alert which presents the abnormal spikes in outbound traffic leaving the company network towards an untrusted zone.
Severity LevelMedium
Threat IndicatorCompromised Host
MITRE ATT&CK TacticsPersistence
Discovery
Collection
Log sourcesFirewall Traffic Logs
False PositivesAsset Inventory Application scanners
Vulnerability scans
(if organization is not blocking outbound traffic in perimeter firewall)
Recommendations1. Review configuration of the internal machine(s) that is/are generating this traffic.
2. Run a EDR scan on the internal host
3. If applicable, quarantine or disconnect the machine from the internal network
4. Review perimeter firewall logs for indicators of large data transferred from internal machine to internet destinations (data leakage)