PH_Rule_Flow_6
Enabled
Detects excessive number of half-open TCP connections from many distinct sources to the same destination host and on the same port in a short period of time. This may indicate that the destination server is under some sort of attack.
7
Security
Impact
Impact consists of techniques that adversaries use to disrupt availability or compromise integrity by manipulating business and operational processes. Techniques used for impact can include destroying or tampering with data. In some cases, business processes can look fine, but may have been altered to benefit the adversaries’ goals. These techniques might be used by adversaries to follow through on their end goal or to provide cover for a confidentiality breach.
https://attack.mitre.org/tactics/TA0040T1498.001
Network Denial of Service: Direct Network Flood
Adversaries may attempt to cause a denial of service (DoS) by directly sending a high-volume of network traffic to a target. Almost any network protocol may be used for flooding. Stateless protocols such as UDP or ICMP are commonly used but stateful protocols such as TCP can be used as well. Botnets are commonly used to conduct network flooding attacks against networks and services. Large botnets can generate a significant amount of traffic from systems spread across the global Internet. In some of the worst cases for distributed DoS (DDoS), so many systems are used to generate the flood that each one only needs to send out a small amount of traffic to produce enough volume to saturate the target network. In such circumstances, distinguishing DDoS traffic from legitimate clients becomes exceedingly difficult.
https://attack.mitre.org/techniques/T1498/001Network
FortiGate via Syslog or Netflow, Checkpoint via Syslog or Netflow, Palo Alto via Syslog or Netflow
Correlation
No remediation guidance specified
If the following pattern or patterns match an ingested event within the given time window in seconds, trigger an incident.
180 seconds
If the following defined pattern/s occur within a 180 second time window.
DDOS_TCP
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
srcDestTCPFlags = 2 AND ipProto = 6 AND eventType IN (Group@PH_SYS_EVENT_BiNetflowTraffic)
This defines how matching events are aggregated, only events with the same matching attribute values are grouped into one unique incident ID
destIpAddr, destIpPort
This is most typically a numerical constraint that defines when the rule should trigger an incident
COUNT (DISTINCT srcIpAddr) >= 200
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 = DDOS_TCP.destIpAddr,
destIpPort = DDOS_TCP.destIpPort,
incidentCount = DDOS_TCP.COUNT (DISTINCT srcIpAddr)