OpenSSH

Overview

OpenSSH is the premier connectivity tool for remote login with the SSH protocol. It encrypts all traffic to eliminate eavesdropping, connection hijacking, and other attacks. In addition, OpenSSH provides a large suite of secure tunneling capabilities, several authentication methods, and sophisticated configuration options.

Setup

This setup guide will show you how to forward logs produced by your OpenSSH servers to SEKOIA.IO by means of an rsyslog transport channel. On most linux servers, two packages need to be installed: rsyslog and rsyslog-gnutls.

1. Download the certificate

In order to allow the connection of your rsyslog server to the SEKOIA.IO intake, please download the SEKOIA.IO intake certificate:

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$ wget -O /etc/rsyslog.d/SEKOIA-IO-intake.pem https://app.sekoia.io/assets/files/SEKOIA-IO-intake.pem

2. Configure the Rsyslog server

By default, the OpenSSH server (sshd) leverages the log level INFO and the system log facility AUTH.

Open or create a new OpenSSH configuration file for rsyslog:

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sudo vim /etc/rsyslog.d/6-openssh.conf

Paste the following rsyslog configuration to trigger the emission of OpenSSH logs by your rsyslog server to SEKOIA.IO:

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# Define the SEKIOA-IO intake certificate
$DefaultNetstreamDriverCAFile /etc/rsyslog.d/SEKOIA-IO-intake.pem

# Configure up the network ssl connection
$ActionSendStreamDriver gtls # use gtls netstream driver
$ActionSendStreamDriverMode 1 # require TLS for the connection
$ActionSendStreamDriverAuthMode x509/name # server is authenticated

# Template definition [RFC5424](https://tools.ietf.org/html/rfc5424#section-7.2.2)
# IMPORTANT: don't forget to set your intake key in the template
template(name="SEKOIAIOOpenSSHTemplate" type="string" string="<%pri%>1 %timestamp:::date-rfc3339% %hostname% %app-name% %procid% LOG [SEKOIA@53288 intake_key=\"YOUR_INTAKE_KEY\"] %msg%\n")

# Send your events to SEKOIA.IO intake servers under SEKOIAIOOpenSSHTemplate template
if $programname startswith 'sshd' then @@(o)intake.sekoia.io:10514;SEKOIAIOOpenSSHTemplate

In the above template instruction, please replace YOUR_INTAKE_KEY variable with your intake key.

3. Restart rsyslog

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$ sudo service rsyslog restart

4. Enjoy your events

Go to the events page to watch your incoming events.

Further Readings