Linux: Netcat Process Activity

Rule ID

PH_Rule_TH_Linux_23

Default Status

Enabled

Description

Netcat Process Activity detected. Netcat is often used as a persistence mechanism by exporting a reverse shell or by serving a shell on a listening port. Netcat is also sometimes used for data exfiltration. Some normal use of this program, while uncommon, may originate from scripts, automation tools, and frameworks. This requires process monitoring via FortiSIEM Linux agent.

Severity

MITRE ATT&CK® Tactics

Execution

Execution consists of techniques that result in adversary-controlled code running on a local or remote system. Techniques that run malicious code are often paired with techniques from all other tactics to achieve broader goals, like exploring a network or stealing data. For example, an adversary might use a remote access tool to run a PowerShell script that does Remote System Discovery.

https://attack.mitre.org/tactics/TA0002

MITRE ATT&CK® Techniques

T1059.004

Command and Scripting Interpreter: Unix Shell

Adversaries may abuse Unix shell commands and scripts for execution. Unix shells are the primary command prompt on Linux and macOS systems. Unix shells can control every aspect of a system, with certain commands requiring elevated privileges. Adversaries may abuse Unix shells to execute various commands or payloads. Interactive shells may be accessed through command and control channels or during lateral movement. Adversaries may also leverage shell scripts to deliver and execute multiple commands on victims or as part of payloads used for persistence.

https://attack.mitre.org/techniques/T1059/004

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 IN ("nc", "ncat", "netcat", "netcat.openbsd", "netcat.traditional")

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