Dynamically generated host name: malware likely

Rule ID

PH_Rule_Vuln_36

Default Status

Disabled

Description

Detects algorthmically generated host name in network traffic - malware often use algorithmically generated host names to communicate.

Severity

MITRE ATT&CK® Tactics

Command And Control

MITRE ATT&CK® Techniques

T1568.002

Dynamic Resolution: Domain Generation Algorithms

Adversaries may make use of Domain Generation Algorithms (DGAs) to dynamically identify a destination domain for command and control traffic rather than relying on a list of static IP addresses or domains. This has the advantage of making it much harder for defenders block, track, or take over the command and control channel, as there potentially could be thousands of domains that malware can check for instructions. Adversaries may use DGAs for the purpose of Fallback Channels. When contact is lost with the primary command and control server malware may employ a DGA as a means to reestablishing command and control.

https://attack.mitre.org/techniques/T1568/002

Impacts

Network

Data Source

FortiGate via Syslog or Netflow,Checkpoint via Syslog or Netflow, Palo Alto via Syslog or Netflow

Detection

Correlation

Remediation Guidance

No remediation guidance specified

Time Window

If the following pattern or patterns match an ingested event within the given time window in seconds, trigger an incident.

300 seconds

Trigger Conditions

If the following defined pattern/s occur within a 300 second time window.

DGAFound

SubPattern Definitions

SubPattern Name: DGAFound

This is the named definition of the event query, this is important if multiple subpatterns are defined to distinguish them.

SubPattern Query

This is the query logic that matches incoming events

eventType = "PH_DEV_MON_DGA_DETECTED"

Group by Attributes

This defines how matching events are aggregated, only events with the same matching attribute values are grouped into one unique incident ID

srcIpAddr,destName

Aggregate Constraint

This is most typically a numerical constraint that defines when the rule should trigger an incident

AVG(domainEntropy) < 7

Incident Attribute Mapping

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 = DGAFound.srcIpAddr,
 destName = DGAFound.destName,
 domainEntropy = DGAFound.AVG(domainEntropy)

FortiSIEM Rules