Analytics Story: Linux Rootkit

Date: 2022-07-27 ID: e30f4054-ac08-4999-b8bc-5cc46886c18d Author: Michael Haag, Splunk Product: Splunk Enterprise Security

Description

Adversaries may use rootkits to hide the presence of programs, files, network connections, services, drivers, and other system components. Rootkits are programs that hide the existence of malware by intercepting/hooking and modifying operating system API calls that supply system information.

Why it matters

Rootkits or rootkit enabling functionality may reside at the user or kernel level in the operating system or lower, to include a hypervisor, Master Boot Record, or System Firmware. Rootkits have been seen for Windows, Linux, and Mac OS X systems. Linux rootkits may not standout as much as a Windows rootkit, therefore understanding what kernel modules are installed today and monitoring for new is important. As with any rootkit, it may blend in using a common kernel name or variation of legitimate names.

Detections

Name ▲▼	Technique ▲▼	Type ▲▼
Linux Auditd Insert Kernel Module Using Insmod Utility	Kernel Modules and Extensions	Anomaly
Linux Auditd Install Kernel Module Using Modprobe Utility	Kernel Modules and Extensions	Anomaly
Linux Auditd Kernel Module Enumeration	System Information Discovery, Rootkit	Anomaly
Linux File Created In Kernel Driver Directory	Kernel Modules and Extensions	Anomaly
Linux Insert Kernel Module Using Insmod Utility	Kernel Modules and Extensions	Anomaly
Linux Install Kernel Module Using Modprobe Utility	Kernel Modules and Extensions	Anomaly
Linux Kernel Module Enumeration	System Information Discovery, Rootkit	Anomaly

Data Sources

Name ▲▼	Platform ▲▼	Sourcetype ▲▼	Source ▲▼
Linux Auditd Syscall	Linux	`auditd`	`auditd`
Sysmon for Linux EventID 1	Linux	`sysmon:linux`	`Syslog:Linux-Sysmon/Operational`
Sysmon for Linux EventID 11	Linux	`sysmon:linux`	`Syslog:Linux-Sysmon/Operational`

References

Source: GitHub | Version: 1