Linux: Mknod Process Activity

Rule ID

PH_Rule_TH_Linux_22

Default Status

Enabled

Description

Mknod Process Activity detected. Linux mknod program is sometimes used in the command payload of a remote command injection and other exploits. It is used to export a command shell when the traditional version of netcat is not available to the payload. Some normal use of this program, at varying levels of frequency, may originate from scripts, automation tools, and frameworks. This requires process monitoring via FortiSIEM Linux agent.

Severity

MITRE ATT&CK® Tactics

Command And Control

MITRE ATT&CK® Techniques

T1071.004

Application Layer Protocol: DNS

Adversaries may communicate using the Domain Name System (DNS) application layer protocol to avoid detection/network filtering by blending in with existing traffic. Commands to the remote system, and often the results of those commands, will be embedded within the protocol traffic between the client and server.

https://attack.mitre.org/techniques/T1071/004

Impacts

Server

Data Source

Linux Process Monitoring via FortiSIEM Agent

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.

Filter

SubPattern Definitions

SubPattern Name: Filter

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 = "LINUX_PROCESS_EXEC" AND procName = "mknod"

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

hostName, user, procName, swParam

Aggregate Constraint

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

COUNT(*) >= 1

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

 hostName = Filter.hostName,
 user = Filter.user,
 procName = Filter.procName,
 swParam = Filter.swParam

FortiSIEM Rules