PH_Rule_Flow_10
Enabled
Detects large (> 200 bytes/pkt) ICMP echo request and response packets - this is unusual since ICMP packets carry minimal information and are small in size. This may indicate that some other traffic is being carried over ICMP protocol.
9
Security
Command And Control
T1095
Non-Application Layer Protocol
Adversaries may use a non-application layer protocol for communication between host and C2 server or among infected hosts within a network. The list of possible protocols is extensive but Specific examples include use of network layer protocols, such as the Internet Control Message Protocol (ICMP), transport layer protocols, such as the User Datagram Protocol (UDP), session layer protocols, such as Socket Secure (SOCKS), as well as redirected/tunneled protocols, such as Serial over LAN (SOL).
https://attack.mitre.org/techniques/T1095Network
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.
300 seconds
If the following defined pattern/s occur within a 300 second time window.
LargeICMPEchoReq AND LargeICMPEchoResp
This defines how two or more distinct events are related in a time-series based action. e.g. An event occurs followed by another event if the source IP, user, and messageId are the same
LargeICMPEchoReq.srcIpAddr = LargeICMPEchoResp.destIpAddr AND LargeICMPEchoReq.destIpAddr = LargeICMPEchoResp.srcIpAddr
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
ipProto = 1 AND icmpType = 8 AND eventType IN (Group@PH_SYS_EVENT_PermitNetTraffic, Group@PH_SYS_EVENT_NetflowTraffic, 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
srcIpAddr, destIpAddr
This is most typically a numerical constraint that defines when the rule should trigger an incident
SUM(sentPkts64) > 0 AND SUM(sentBytes64)/SUM(sentPkts64) >= 200
Operator Rank: 0 Operator Type: AND
This operator defines the logic condition relating to the prior event subpattern clause and the following event subpattern clause
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
ipProto = 1 AND icmpType = 0 AND eventType IN (Group@PH_SYS_EVENT_PermitNetTraffic, Group@PH_SYS_EVENT_NetflowTraffic, 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
srcIpAddr, destIpAddr
This is most typically a numerical constraint that defines when the rule should trigger an incident
SUM(sentPkts64) > 0 AND SUM(sentBytes64)/SUM(sentPkts64) >= 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
srcIpAddr = LargeICMPEchoReq.srcIpAddr,
destIpAddr = LargeICMPEchoReq.destIpAddr