2. Quickstart guide
This guide will give you a quick start to run Suricata and will focus only on the basics. For more details, read through the more specific chapters.
2.1. Installation
It's assumed that you run a recent Ubuntu release as the official PPA can be used for the installation.
Installation steps:
sudo add-apt-repository ppa:oisf/suricata-stable
sudo apt update
sudo apt install suricata jq
The dedicated PPA repository is added, and after updating the index, Suricata can
be installed. We recommend installing the jq
tool at this time as it will help
with displaying information from Suricata's EVE JSON output (described later in this guide).
For the installation on other systems or to use specific compile options see Installation.
After installing Suricata, you can check what version of Suricata you have running and with what options as well as the service state:
sudo suricata --build-info
sudo systemctl status suricata
2.2. Basic setup
First, determine the interface(s) and IP address(es) on which Suricata should be inspecting network packets:
$ ip addr
2: enp1s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
link/ether 00:11:22:33:44:55 brd ff:ff:ff:ff:ff:ff
inet 10.0.0.23/24 brd 10.23.0.255 scope global noprefixroute enp1s0
Use that information to configure Suricata:
sudo vim /etc/suricata/suricata.yaml
There are many possible configuration options, we focus on the setup of
the HOME_NET
variable and the network interface configuration. The
HOME_NET
variable should include, in most scenarios, the IP address of
the monitored interface and all the local networks in
use. The default already includes the RFC 1918 networks. In this example
10.0.0.23
is already included within 10.0.0.0/8
. If no other networks
are used the other predefined values can be removed.
In this example the interface name is enp1s0
so the interface name in the
af-packet
section needs to match. An example interface config might
look like this:
Capture settings:
af-packet:
- interface: enp1s0
cluster-id: 99
cluster-type: cluster_flow
defrag: yes
use-mmap: yes
tpacket-v3: yes
This configuration uses the most recent recommended settings for the IDS runmode for basic setups. There are many of possible configuration options which are described in dedicated chapters and are especially relevant for high performance setups.
2.3. Signatures
Suricata uses Signatures to trigger alerts so it's necessary to install those
and keep them updated. Signatures are also called rules, thus the name
rule-files. With the tool suricata-update
rules can be fetched, updated and
managed to be provided for Suricata.
In this guide we just run the default mode which fetches the ET Open ruleset:
sudo suricata-update
Afterwards the rules are installed at /var/lib/suricata/rules
which is also
the default at the config and uses the sole suricata.rules
file.
2.4. Running Suricata
With the rules installed, Suricata can run properly and thus we restart it:
sudo systemctl restart suricata
To make sure Suricata is running check the Suricata log:
sudo tail /var/log/suricata/suricata.log
The last line will be similar to this:
<Notice> - all 4 packet processing threads, 4 management threads initialized, engine started.
The actual thread count will depend on the system and the configuration.
To see statistics, check the stats.log
file:
sudo tail -f /var/log/suricata/stats.log
By default, it is updated every 8 seconds to show updated values with the current state, like how many packets have been processed and what type of traffic was decoded.
2.5. Alerting
To test the IDS functionality of Suricata it's best to test with a signature. The signature with
ID 2100498
from the ET Open ruleset is written specific for such test cases.
2100498:
alert ip any any -> any any (msg:"GPL ATTACK_RESPONSE id check returned root"; content:"uid=0|28|root|29|"; classtype:bad-unknown; sid:2100498; rev:7; metadata:created_at 2010_09_23, updated_at 2010_09_23;)
The syntax and logic behind those signatures is covered in other chapters. This
will alert on any IP traffic that has the content within its payload. This rule
can be triggered quite easy. Before we trigger it, start tail
to see updates to
fast.log
.
Rule trigger:
sudo tail -f /var/log/suricata/fast.log
curl http://testmynids.org/uid/index.html
The following output should now be seen in the log:
[1:2100498:7] GPL ATTACK_RESPONSE id check returned root [**] [Classification: Potentially Bad Traffic] [Priority: 2] {TCP} 217.160.0.187:80 -> 10.0.0.23:41618
This should include the timestamp and the IP of your system.
2.6. EVE Json
The more advanced output is the EVE JSON output which is explained in detail in
Eve JSON Output. To see what this looks like it's
recommended to use jq
to parse the JSON output.
Alerts:
sudo tail -f /var/log/suricata/eve.json | jq 'select(.event_type=="alert")'
This will display more detail about each alert, including meta-data.
Stats:
sudo tail -f /var/log/suricata/eve.json | jq 'select(.event_type=="stats")|.stats.capture.kernel_packets'
sudo tail -f /var/log/suricata/eve.json | jq 'select(.event_type=="stats")'
The first example displays the number of packets captured by the kernel; the second examples shows all of the statistics.