Sysmon for Linux

Sysmon for Linux is a tool that monitors and logs system activity including process lifetime, network connections, file system writes, and more. Sysmon works across reboots and uses advanced filtering to help identify malicious activity as well as how intruders and malware operate on your network. Sysmon for Linux is part of Sysinternals.

Installation

The packages are available in the official Microsoft Linux repositories and instructions on how to install the packages for the different Linux distributions can be found in the Installation instructions.

This project contains the code for build and installing Sysmon on Linux.

Build

Please see build instructions here.

Autodiscovery of Offsets

On systems that are BTF enabled, Sysmon will use BTF for accurate kernel offsets. Sysmon also supports specifying standalone BTF files (using /BTF switch). There are several ways to generate BTF files and BTFHub has a number of standalone BTF files for different distributions/kernels.

If BTF isn't available, Sysmon attempts to automatically discover the offsets of some members of some kernel structs. If this fails, please provide details of the kernel version (and config if possible) plus the error message to the GitHub issues page.

You can then generate a configuration file to override the autodiscovery by building the getOffsets module in the /opt/sysinternals/getOffsets directory. See the README.md in that directory for more information.

Manual Page

A man page for Sysmon can be found in the package directory, and is installed by both deb and rpm packages.

Use 'find' on the package directory to locate it manually.

Output

sudo tail -f /var/log/syslog

or more human-readable

sudo tail -f /var/log/syslog | sudo /opt/sysmon/sysmonLogView

SysmonLogView has options to filter the output to make it easy to identify specific events or reduce outputted fields for brevity.

SysmonLogView is built when Sysmon is built and is installed into /opt/sysmon when sysmon is installed.

Important: You may wish to modify your Syslogger config to ensure it can handle particularly large events (e.g. >64KB, as defaults are often between 1KB and 8KB), and/or use the FieldSizes configuration entry to limit the length of output for some fields, such as CommandLine, Image, CurrentDirectory, etc.

Example:

Add <FieldSizes>CommandLine:100,Image:20</FieldSizes> under <Sysmon> in your configuration file.

Developer Details

See DEVELOP.md

License

Sysmon For Linux is licensed under MIT, with the eBPF programs licensed under GPL2. SysinternalsEBPF (on which Sysmon For Linux depends) is licensed under LGPL2.1, with the eBPF code library licensed under GPL2.