Posts Tagged: NIDS
Installing Snort++ in Ubuntu (Version 3.0 Alpha 4 build 245)
The instructions below show how to install Snort 3 alpha 4 build 245 on Ubuntu. This install has been tested on Ubuntu 14, 16, and 18, for the x64 architecture. For an outdated Ubuntu 12 version of these instructions, please go here. Note that Snort 3 is Alpha software, and therefore has bugs and issues, and should be installed for testing purposes only (not on production systems).
Snort 3 Alpha 4 Build 245 was released on May 24th, 2018, and this guide has been tested with that version (releases after this specific release may not follow the same steps). Generic build instructions, prerequisites, and detailed notes are available in the manual.
If you want a more in-depth explanation of the install steps, which are very similar to the 2.9.9.x version of Snort, as well as instructions on how to configure and enhance Snort’s functionality, see my series on installing Snort 2.9.9.x on Ubuntu.
So let’s get started. First, we will create a directory to save the downloaded tarball files:
mkdir ~/snort_src cd ~/snort_src
Next we need to install all the Snort pre-requisites from the Ubuntu repositories:
sudo apt-get install -y build-essential autotools-dev libdumbnet-dev libluajit-5.1-dev libpcap-dev libpcre3-dev zlib1g-dev pkg-config libhwloc-dev
For Ubuntu 16 and 18, you can install cmake from the default repository:
# Ubuntu 16 and 18 (and greater) only: sudo apt-get install -y cmake
For Ubuntu 14, you have to install cmake from source, because the version in the Ubuntu repository is too old to compile Snort:
# Ubuntu 14 only sudo apt-get remove -y cmake cd ~/snort_src wget https://cmake.org/files/v3.10/cmake-3.10.3.tar.gz tar -xzvf cmake-3.10.3.tar.gz cd cmake-3.10.3 ./bootstrap make sudo make install
Note: If you are running Ubuntu 14 x86, you must install a newer version of gcc, either from a ppa or from source. Snort will not compile properly on the x86 platform with the version of gcc in the Ubuntu repository (4.8.4). I do not cover these steps in this guide, but you can easily google this process. This does not apply to the x64 version of Ubuntu 14 which you can easily install using the steps below.
Install the optional (recommended) software:
sudo apt-get install -y liblzma-dev openssl libssl-dev cpputest libsqlite3-dev uuid-dev
Install tools required for compiling the source from github:
sudo apt-get install -y libtool git autoconf
Install the DAQ pre-requisites:
sudo apt-get install -y bison flex
If you want to build the documentation as well (not really needed, unless you want it, usually about 700 MB of libraries):
sudo apt-get install -y asciidoc dblatex source-highlight w3m
If you want to run Snort in inline mode using NFQ, install the required packages (not required for IDS mode or inline mode using afpacket). If you’re unsure, you should install this package.
sudo apt-get install -y libnetfilter-queue-dev
Next, compile and install safec for runtime bounds checks on certain legacy C-library calls (this is optional but recommended):
cd ~/snort_src wget http://downloads.sourceforge.net/project/safeclib/libsafec-10052013.tar.gz tar -xzvf libsafec-10052013.tar.gz cd libsafec-10052013 ./configure make sudo make install
Download and install gperftools 2.7, google’s thread-caching malloc (used in chrome). Tcmalloc is a memory allocator that’s optimized for high concurrency situations which will provide better speed for the trade-off of higher memory usage. We don’t want the version of tcmalloc from the repositories (version 2.5 in libgoogle-perftools-dev) as they don’t work with Snort. Tcmalloc is optional but recommended:
cd ~/snort_src wget https://github.com/gperftools/gperftools/releases/download/gperftools-2.7/gperftools-2.7.tar.gz tar xzvf gperftools-2.7.tar.gz cd gperftools-2.7 ./configure make sudo make install
One of the Snort recommended prerequisites is Hyperscan 4.4.0. From their webpage: “Hyperscan is a regular expression engine designed to offer high performance, the ability to match multiple expressions simultaneously and flexibility in scanning operation.” Hyperscan needs Ragel 6.9 and the Boost header libraries.
Install Ragel 6.10 from source:
cd ~/snort_src wget http://www.colm.net/files/ragel/ragel-6.10.tar.gz tar -xzvf ragel-6.10.tar.gz cd ragel-6.10 ./configure make sudo make install
Download the Boost 1.67.0 libraries, but do not install:
cd ~/snort_src wget https://dl.bintray.com/boostorg/release/1.67.0/source/boost_1_67_0.tar.gz tar -xvzf boost_1_67_0.tar.gz
Install Hyperscan 4.7.0 from source, referencing the location of the Boost source directory:
cd ~/snort_src wget https://github.com/intel/hyperscan/archive/v4.7.0.tar.gz tar -xvzf v4.7.0.tar.gz mkdir ~/snort_src/hyperscan-4.7.0-build cd hyperscan-4.7.0-build/ cmake -DCMAKE_INSTALL_PREFIX=/usr/local -DBOOST_ROOT=~/snort_src/boost_1_67_0/ ../hyperscan-4.7.0 make sudo make install
If you want to test that Hyperscan works, from the build directory, run:
cd ~/snort_src/hyperscan-4.7.0-build/ ./bin/unit-hyperscan
The unit tests will run (this takes a few minutes).
Snort has an optional requirement for flatbuffers, A memory efficient serialization library:
cd ~/snort_src wget https://github.com/google/flatbuffers/archive/v1.9.0.tar.gz -O flatbuffers-v1.9.0.tar.gz tar -xzvf flatbuffers-1.9.0.tar.gz mkdir flatbuffers-build cd flatbuffers-build cmake ../flatbuffers-1.9.0 make sudo make install
Download and install Data AcQuisition library (DAQ) from the Snort website (note that DAQ for Snort 3 is a different DAQ than for the 2.9.9.x series of Snort):
cd ~/snort_src wget https://www.snort.org/downloads/snortplus/daq-2.2.2.tar.gz tar -xvzf daq-2.2.2.tar.gz cd daq-2.2.2 ./configure make sudo make install
Run the following command to update shared libraries:
sudo ldconfig
Now we are ready to install Snort from source. This command downloads and installs the latest version of Snort 3 (currently 3.0.0 Alpha 4, build 245, but as the codebase is updated, you’ll get a newer version).
If you want to install all the snort directories under a single directory, see the section at the bottom of this document titled Changing the install location of Snort. Here we choose to install Snort to the /usr/local directory (the standard location for additional software from the LSB)
cd ~/snort_src git clone git://github.com/snortadmin/snort3.git cd snort3 ./configure_cmake.sh --prefix=/usr/local cd build make sudo make install
Optional: If you are interested in seeing what additional options can be configured when building Snort, run ./configure cmake.sh ‐‐help for a full list. Some options you may be interested in is the Snort3 command line shell (‐‐enable-shell) or support for pcap files over 2 GB (‐‐enable-large-pcap).
Snort 3 requires a few environmental variables, we store them temporarily in the current session so we can continue working, and save them permanently to the ~/.bashrc file (you’ll need to do this for every user profile):
export LUA_PATH=/usr/local/include/snort/lua/\?.lua\;\; export SNORT_LUA_PATH=/usr/local/etc/snort sh -c "echo 'export LUA_PATH=/usr/local/include/snort/lua/\?.lua\;\;' >> ~/.bashrc" sh -c "echo 'export SNORT_LUA_PATH=/usr/local/etc/snort' >> ~/.bashrc"
to ensure that these two environmental variables are available when using sudo, we need to add them to the /etc/sudoers file:
sudo visudo
in the editor, add the following to to the bottom of the file:
Defaults env_keep += "LUA_PATH SNORT_LUA_PATH"
use ctrl-x to exit, save when prompted by pressing y, then press enter to save the file to /etc/sudoers.tmp (which will get copied automatically to /etc/sudoers).
The last step of our Snort installation is to test that the Snort Binary runs. Execute Snort with the -V flag, which causes Snort to print the current version. You should see output similar to the following:
user@snort3:~$ snort -V
,,_ -*> Snort++ <*-
o" )~ Version 3.0.0-a4 (Build 245) from 2.9.11
'''' By Martin Roesch & The Snort Team
http://snort.org/contact#team
Copyright (C) 2014-2017 Cisco and/or its affiliates. All rights reserved.
Copyright (C) 1998-2013 Sourcefire, Inc., et al.
Using DAQ version 2.2.2
Using LuaJIT version 2.1.0-beta3
Using OpenSSL 1.1.0g 2 Nov 2017
Using libpcap version 1.8.1
Using PCRE version 8.39 2016-06-14
Using ZLIB version 1.2.11
Using FlatBuffers 1.9.0
Using Hyperscan version 4.7.0 2018-06-12
Using LZMA version 5.2.2
user@snort3:~$
A note on install locations:
When you install snort to /usr/local, you get the following folder structure:
user@snort3x86:/opt/snort$ tree /usr/local -L 3
/usr/local
├── bin
│ ├── fbstreamer
│ ├── snort
│ ├── snort2lua
│ ├── u2boat
│ └── u2spewfoo
├── etc
│ └── snort
│ ├── file_magic.lua
│ ├── snort_defaults.lua
│ └── snort.lua
├── include
│ └── snort
│ ├── actions
│ ├── codecs
│ ├── daqs
│ ├── decompress
│ ├── detection
│ ├── events
│ ├── file_api
│ ├── flow
│ ├── framework
│ ├── hash
│ ├── log
│ ├── lua
│ ├── main
│ ├── managers
│ ├── mime
│ ├── packet_io
│ ├── profiler
│ ├── protocols
│ ├── pub_sub
│ ├── search_engines
│ ├── sfip
│ ├── stream
│ ├── time
│ └── utils
├── lib
│ ├── pkgconfig
│ │ └── snort.pc
│ └── snort
│ └── daqs
└── share
└── doc
└── snort
38 directories, 8 files
The /usr/local/bin folder contains the following Snort binaries:
- fbstreamer : A utility for accessing the statistics generated in flatbuffer format.
- snort : The Snort binary.
- snort2lua : Tool to convert a Snort 2.9.8.x configuration file into a 3.x configuration file. More notes here.
- u2boat : U2boat is a tool for converting unified2 files into different formats.
- u2spewfoo: U2SpewFoo is a lightweight tool for dumping the contents of unified2 files to stdout.
Additionally, the following folders are created / used:
- /opt/snort/bin : Binaries for Snort and supporting software.
- /opt/snort/etc/snort : The configuration files for Snort.
- /opt/snort/include/snort : All include files for Snort.
- /opt/snort/lib/pkgconfig : The pkgconfig file for Snort (compilation details for Snort).
- /opt/snort/share/doc/snort : The documentation for the installed version of Snort.
Changing the install location of Snort
If you would rather have all these folders install to a single-folder location for testing (/opt/snort), add ‑‑prefix=/opt/snort to the ./configure command when preparing to build Snort. This will install all these folders under the path you choose. You also need to modify some of the other paths detailed above, so if you decide to install in that manner, you should follow the install instructions detailed in the Snort blog.
Snort Rules
Snort3 rules have more options than Snort 2 rules, and while the normal rules downloaded with PulledPork or manually will work, for testing you will probably want to download the set of community rules specificallycreated for snort3. You can manually download snort3 specific community rules from the snort website:
cd ~/snort_src/ wget https://www.snort.org/downloads/community/snort3-community-rules.tar.gz tar -xvzf snort3-community-rules.tar.gz cd snort3-community-rules sudo mkdir /usr/local/etc/snort/rules sudo mkdir /usr/local/etc/snort/builtin_rules sudo mkdir /usr/local/etc/snort/so_rules sudo mkdir /usr/local/etc/snort/lists sudo cp snort3-community.rules /usr/local/etc/snort/rules/ sudo cp sid-msg.map /usr/local/etc/snort/rules/
now test that snort can load these rules:
snort -c /usr/local/etc/snort/snort.lua -R /usr/local/etc/snort/rules/snort3-community.rules
your output should contain something similar:
Loading rules: Loading /opt/snort/etc/snort/rules/snort3-community.rules: Finished /opt/snort/etc/snort/rules/snort3-community.rules. Finished rules. -------------------------------------------------- rule counts total rules loaded: 829 text rules: 829 option chains: 829 chain headers: 46 -------------------------------------------------- ...
you may want to run Snort with the following flags to detect issues: the warn-all and pedantic flags. From the Snort3 manual:
Warnings are not emitted unless –warn-* is specified. –warn-all enables all warnings, and –pedantic makes such warnings fatal
Installing OpenAppID
OpenAppID allows for the identification of application layer traffic. The Snort team has put together a package of detectors, with assistance from the community that you can download and install, called the Application Detector Package which needs to be installed. First download the OpenAppID detector package:
cd ~/snort_src/ wget https://www.snort.org/downloads/openappid/7630 -O OpenAppId-7630.tar.gz tar -xzvf OpenAppId-7630.tar.gz sudo cp -R odp /usr/local/lib/
Now we need to edit our snort configuration file to point to this odp directory:
sudo vi /usr/local/etc/snort/snort.lua
At line 113 (yours line number may be slightly different) you will see the appid= entry. You will want to add the app detector dir option here, pointing to the parent folder of the odf folder. It should look like this:
appid =
{
app_detector_dir = '/usr/local/lib',
}
note that you must have four spaces (not a tab) for the indented line. Now we want to test the configuration file loads correctly:
snort -c /usr/local/etc/snort/snort.lua --warn-all
you should see output similar to:
... Snort successfully validated the configuration (with 0 warnings). o")~ Snort exiting
Now to load Snort with the OpenAppID detectors, as well as all rules (we omit the pedantic flag, since the rules will throw flowbit warnings that are non fatal and can be ignored:)
snort -c /usr/local/etc/snort/snort.lua -R /usr/local/etc/snort/rules/snort3-community.rules --warn-all
Create a simple rule to test that OpenAppID is working correctly:
sudo touch /usr/local/etc/snort/rules/local.rules sudo vi /usr/local/etc/snort/rules/local.rules
with the following content:
alert tcp any any -> any any ( msg:"Facebook trafic Seen"; appids:"Facebook";sid:10000001; )
test to make sure the rule loads correctly:
snort -c /usr/local/etc/snort/snort.lua -R /opt/snort/etc/snort/rules/local.rules --warn-all
You should see one rule loaded successfully. Now let’s run snort in detection mode on an interface (change eth0 below to match your interface name), printing alerts to the console:
sudo snort -c /usr/local/etc/snort/snort.lua -R /usr/local/etc/snort/rules/local.rules -i eth0 -A alert_fast -k none
the -k none flag tells Snort to ignore bad checksums. the Stream and Frag decoders will drop packets that have bad checksums, and the packets will not get processed by the OpenAppID detectors. By including this flag, we ensure that a packet with a bad checksum still gets processed. Now from another window on that computer (open a new terminal window or a second ssh session), use wget
to connect to facebook:
wget facebook.com
from the first console window you will see alerts output similar to the following:
08/05−19:13:45.451834 [∗∗] [1:10000001:0] ”Facebook trafic Seen” [∗∗] [Priority: 0] [AppID: Facebook] {TCP} 157.240.1.35:443 −> 10.0.0.104:33882
08/05−19:13:45.451842 [∗∗] [1:10000001:0] ”Facebook trafic Seen” [∗∗] [Priority: 0] [AppID: Facebook] {TCP} 10.0.0.104:33882 −> 157.240.1.35:443
use ctrl-c to stop Snort.
Note: if you are collecting packets with a larger MTU that the standard MTU for your adapter (VLAN tagged packets, MPLS Packets, packets from a different network type with a larger MTU), you may need to use the –snaplen flag to adjust snort to process larger packets)
Where to go from here
If you want to learn more about how to run the 2.9.9.x version of Snort, and how to install additional software to enhance a Snort system, see my series on installing Snort on Ubuntu. If you want to develop Snort plugins, please see my guide: Installing Snort++ Example Plugins.
I would love to get feedback from you about this guide. Recommendations, issues, or ideas, please contact me here.
Installing Snort++ in Ubuntu (Version 3.0 Alpha 4 build 240)
NOTE: this article is out of date and has been replaced with a newer article: Installing Snort++ (Snort 3 Alpha 4 build 245) in Ubuntu
The instructions below show how to install Snort 3 alpha 4 build 240 on Ubuntu. This install has been tested on Ubuntu 14 and 16, for both the x86 and x64 architectures. For an outdated Ubuntu 12 version of these instructions, please go here. Note that Snort 3 is Alpha software, and therefore has bugs and issues, and should be installed for testing purposes only (not on production systems).
Snort 3 Alpha 4 Build 240 was released on November 1st, 2017, and this guide has been tested with that version (releases after this specific release may not follow the same steps). Generic build instructions, prerequisites, and detailed notes are available in the manual.
If you want a more in-depth explanation of the install steps, which are very similar to the 2.9.9.x version of Snort, as well as instructions on how to configure and enhance Snort’s functionality, see my series on installing Snort 2.9.9.x on Ubuntu.
So let’s get started. First we need to install all the Snort pre-requisites from the Ubuntu repositories:
sudo apt-get install -y build-essential autotools-dev libdumbnet-dev libluajit-5.1-dev libpcap-dev libpcre3-dev zlib1g-dev pkg-config libhwloc-dev cmake
Install the optional (recommended) software:
sudo apt-get install -y liblzma-dev openssl libssl-dev cpputest libsqlite3-dev uuid-dev
Install tools required for compiling the source from github:
sudo apt-get install -y libtool git autoconf
Install the DAQ pre-requisites:
sudo apt-get install -y bison flex
If you want to build the documentation as well (not really needed, unless you want it, usually about 700 MB of libraries):
sudo apt-get install -y asciidoc dblatex source-highlight w3m
If you want to run Snort in inline mode using NFQ, install the required packages (not required for IDS mode or inline mode using afpacket). If you’re unsure, you should install this package.
sudo apt-get install -y libnetfilter-queue-dev
Next we will create a directory to save the downloaded tarball files:
mkdir ~/snort_src cd ~/snort_src
First and install safec for runtime bounds checks on certain legacy C-library calls (this is optional but recommended):
cd ~/snort_src wget http://downloads.sourceforge.net/project/safeclib/libsafec-10052013.tar.gz tar -xzvf libsafec-10052013.tar.gz cd libsafec-10052013 ./configure make sudo make install
One of the Snort recommended prerequisites is Hyperscan 4.4.0. From their webpage: “Hyperscan is a regular expression engine designed to offer high performance, the ability to match multiple expressions simultaneously and flexibility in scanning operation.” Hyperscan needs Ragel 6.9 and the Boost header libraries.
Install Ragel 6.10 from source:
cd ~/snort_src wget http://www.colm.net/files/ragel/ragel-6.10.tar.gz tar -xzvf ragel-6.10.tar.gz cd ragel-6.10 ./configure make sudo make install
Download the Boost 1.65.1 libraries, but do not install:
cd ~/snort_src wget https://dl.bintray.com/boostorg/release/1.65.1/source/boost_1_65_1.tar.gz tar -xvzf boost_1_65_1.tar.gz
Install Hyperscan 4.6.0 from source, referencing the location of the Boost source directory:
cd ~/snort_src wget https://github.com/intel/hyperscan/archive/v4.6.0.tar.gz tar -xvzf v4.6.0.tar.gz mkdir ~/snort_src/hyperscan-4.6.0-build cd hyperscan-4.6.0-build/ cmake -DCMAKE_INSTALL_PREFIX=/usr/local -DBOOST_ROOT=~/snort_src/boost_1_65_1/ ../hyperscan-4.6.0 make sudo make install
If you want to test that Hyperscan works, from the build directory, run:
cd ~/snort_src/hyperscan-4.6.0-build/ ./bin/unit-hyperscan
The unit tests will run (this takes a few minutes).
Snort has an optional requirement for flatbuffers, A memory efficient serialization library:
cd ~/snort_src wget https://github.com/google/flatbuffers/archive/master.tar.gz -O flatbuffers-master.tar.gz tar -xvzf flatbuffers-master.tar.gz mkdir flatbuffers-build cd flatbuffers-build cmake ../flatbuffers-master make sudo make install
Download and install Data AcQuisition library (DAQ) from the Snort website (note that DAQ for Snort 3 is a different DAQ than for the 2.9.9.x series of Snort):
cd ~/snort_src wget https://www.snort.org/downloads/snortplus/daq-2.2.2.tar.gz tar -xvzf daq-2.2.2.tar.gz cd daq-2.2.2 ./configure make sudo make install
Run the following command to update shared libraries:
sudo ldconfig
Now we are ready to install Snort from source. This command downloads and installs the latest version of Snort 3 (currently 3.0.0 Alpha 4, build 239, but as the codebase is updated, you’ll get a newer version). If you want to specifically download the version used in this guide, use this URL instead with wget below: https://github.com/snortadmin/snort3/archive/BUILD_239.tar.gz.
If you want to install all the snort directories under a single directory, see the section at the bottom of this document titled Changing the install location of Snort. Here we choose to install the entire Snort directory structure to a single folder under /opt/:
cd ~/snort_src wget https://github.com/snortadmin/snort3/archive/master.tar.gz tar -xvzf master.tar.gz cd snort3-master/ autoreconf -isvf ./configure --prefix=/opt/snort make sudo make install
Since the Snort installation places the Snort binary at /opt/snort/bin/snort, it is common to create a symlink to /usr/sbin/snort:
sudo ln -s /opt/snort/bin/snort /usr/sbin/snort
Snort 3 requires a few environmental variables, we store them temporarily in the current session so we can continue working, and save them permanently to the ~/.bashrc file (you’ll need to do this for every user profile):
export LUA_PATH=/opt/snort/include/snort/lua/\?.lua\;\; export SNORT_LUA_PATH=/opt/snort/etc/snort sh -c "echo 'export LUA_PATH=/opt/snort/include/snort/lua/\?.lua\;\;' >> ~/.bashrc" sh -c "echo 'export SNORT_LUA_PATH=/opt/snort/etc/snort' >> ~/.bashrc"
to ensure that these two environmental variables are available when using sudo, we need to add them to the /etc/sudoers file:
sudo visudo
in the editor, add the following to to the bottom of the file:
Defaults env_keep += "LUA_PATH SNORT_LUA_PATH"
use ctrl-x to exit, save when prompted by pressing y, then press enter to save the file to /etc/sudoers.tmp (which will get copied automatically to /etc/sudoers).
The last step of our Snort installation is to test that the Snort Binary runs. Execute Snort with the -V flag, which causes Snort to print the current version. You should see output similar to the following:
user@snort3:~$ snort -V
,,_ -*> Snort++ <*-
o" )~ Version 3.0.0-a4 (Build 240) from 2.9.8-383
'''' By Martin Roesch & The Snort Team
http://snort.org/contact#team
Copyright (C) 2014-2017 Cisco and/or its affiliates. All rights reserved.
Copyright (C) 1998-2013 Sourcefire, Inc., et al.
Using DAQ version 2.2.2
Using LuaJIT version 2.0.4
Using OpenSSL 1.0.2g 1 Mar 2016
Using libpcap version 1.7.4
Using PCRE version 8.38 2015-11-23
Using ZLIB version 1.2.8
Using FlatBuffers 1.7.0
Using Hyperscan version 4.6.0 2017-11-04
Using LZMA version 5.1.0alpha
user@snort3:~$
A note on install locations:
When you install snort to /opt/snort, you get the following folder structure:
user@snort3x86:/opt/snort$ tree /opt/snort -L 3
/opt/snort
├── bin
│ ├── fbstreamer
│ ├── snort
│ ├── snort2lua
│ ├── u2boat
│ └── u2spewfoo
├── etc
│ └── snort
│ ├── file_magic.lua
│ ├── snort_defaults.lua
│ └── snort.lua
├── include
│ └── snort
│ ├── actions
│ ├── codecs
│ ├── daqs
│ ├── decompress
│ ├── detection
│ ├── events
│ ├── file_api
│ ├── flow
│ ├── framework
│ ├── hash
│ ├── log
│ ├── lua
│ ├── main
│ ├── managers
│ ├── mime
│ ├── packet_io
│ ├── profiler
│ ├── protocols
│ ├── pub_sub
│ ├── search_engines
│ ├── sfip
│ ├── stream
│ ├── time
│ └── utils
├── lib
│ ├── pkgconfig
│ │ └── snort.pc
│ └── snort
│ └── daqs
└── share
└── doc
└── snort
38 directories, 8 files
The /opt/snort/bin folder contains the following Snort binaries:
- fbstreamer : A utility for accessing the statistics generated in flatbuffer format.
- snort : The Snort binary.
- snort2lua : Tool to convert a Snort 2.9.8.x configuration file into a 3.x configuration file. More notes here.
- u2boat : U2boat is a tool for converting unified2 files into different formats.
- u2spewfoo: U2SpewFoo is a lightweight tool for dumping the contents of unified2 files to stdout.
Additionally, the following folders are created / used:
- /opt/snort/bin : Binaries for Snort and supporting software.
- /opt/snort/etc/snort : The configuration files for Snort.
- /opt/snort/include/snort : All include files for Snort.
- /opt/snort/lib/pkgconfig : The pkgconfig file for Snort (compilation details for Snort).
- /opt/snort/share/doc/snort : The documentation for the installed version of Snort.
Changing the install location of Snort
If you would rather have all these folders install to a more normal location (/usr/local) , add ‑‑prefix=/usr/local/ to the ./configure command when preparing to build Snort. This will install all these folders under the path you choose. You also need to modify some of the other paths detailed above, so if you decide to install in that manner, you should follow the install instructions detailed in the Snort blog.
Snort Rules
Snort3 rules have more options than Snort 2 rules, and while the normal rules downloaded with PulledPork or manually will work, for testing you will probably want to download the set of community rules specificallycreated for snort3. You can manually download snort3 specific community rules from the snort website:
cd ~/snort_src/ wget https://www.snort.org/downloads/community/snort3-community-rules.tar.gz tar -xvzf snort3-community-rules.tar.gz cd snort3-community-rules sudo mkdir /opt/snort/etc/snort/rules sudo cp snort3-community.rules /opt/snort/etc/snort/rules/ sudo cp sid-msg.map /opt/snort/etc/snort/rules/
now test that snort can load these rules:
/opt/snort/bin/snort -c /opt/snort/etc/snort/snort.lua -R /opt/snort/etc/snort/rules/snort3-community.rules
your output should contain something similar:
Loading rules: Loading /opt/snort/etc/snort/rules/snort3-community.rules: Finished /opt/snort/etc/snort/rules/snort3-community.rules. Finished rules. -------------------------------------------------- rule counts total rules loaded: 3462 text rules: 3462 option chains: 3462 chain headers: 264 -------------------------------------------------- ...
you may want to run Snort with the following flags to detect issues: the warn-all and pedantic flags. From the Snort3 manual:
Warnings are not emitted unless –warn-* is specified. –warn-all enables all warnings, and –pedantic makes such warnings fatal
Installing OpenAppID
OpenAppID allows for the identification of application layer traffic. The Snort team has put together a package of detectors, with assistance from the community that you can download and install, called the Application Detector Package which needs to be installed. First download the OpenAppID detector package:
cd ~/snort_src/ wget https://www.snort.org/downloads/openappid/5759 -O OpenAppId-6329 tar -xzvf OpenAppId-6329 sudo cp -R odp /opt/snort/lib/
Now we need to edit our snort configuration file to point to this odp directory:
sudo vi /opt/snort/etc/snort/snort.lua
At line 113 (yours line number may be slightly different) you will see the appid= entry. You will want to add the app detector dir option here, pointing to the parent folder of the odf folder. It should look like this:
appid =
{
app_detector_dir = '/opt/snort/lib',
}
note that you must have four spaces (not a tab) for the indented line. Now we want to test the configuration file loads correctly:
/opt/snort/bin/snort -c /opt/snort/etc/snort/snort.lua --warn-all
you should see output similar to:
... Snort successfully validated the configuration (with 0 warnings). o")~ Snort exiting
Now to load Snort with the OpenAppID detectors, as well as all rules (we omit the pedantic flag, since the rules will throw flowbit warnings that are non fatal and can be ignored:)
/opt/snort/bin/snort -c /opt/snort/etc/snort/snort.lua -R /opt/snort/etc/snort/rules/snort3-community.rules --warn-all
Create a simple rule to test that OpenAppID is working correctly:
sudo touch /opt/snort/etc/snort/rules/local.rules sudo vi /opt/snort/etc/snort/rules/local.rules
with the following content:
alert tcp any any -> any any ( msg:"Facebook trafic Seen"; appids:"Facebook";sid:10000001; )
test to make sure the rule loads correctly:
/opt/snort/bin/snort -c /opt/snort/etc/snort/snort.lua -R /opt/snort/etc/snort/rules/local.rules --warn-all
You should see one rule loaded successfully. Now let’s run snort in detection mode on an interface (change eth0 below to match your interface name), printing alerts to the console:
sudo /opt/snort/bin/snort -c /opt/snort/etc/snort/snort.lua -R /opt/snort/etc/snort/rules/local.rules -i eth0 -A alert_fast -k none
the -k none flag tells Snort to ignore bad checksums. the Stream and Frag decoders will drop packets that have bad checksums, and the packets will not get processed by the OpenAppID detectors. By including this flag, we ensure that a packet with a bad checksum still gets processed. Now from another window on that computer (open a new terminal window or a second ssh session), use wget
to connect to facebook:
wget facebook.com
from the first console window you will see alerts output similar to the following:
08/05−19:13:45.451834 [∗∗] [1:10000001:0] ”Facebook trafic Seen” [∗∗] [Priority: 0] [AppID: Facebook] {TCP} 157.240.1.35:443 −> 10.0.0.104:33882
08/05−19:13:45.451842 [∗∗] [1:10000001:0] ”Facebook trafic Seen” [∗∗] [Priority: 0] [AppID: Facebook] {TCP} 10.0.0.104:33882 −> 157.240.1.35:443
use ctrl-c to stop Snort.
Note: if you are collecting packets with a larger MTU that the standard MTU for your adapter (VLAN tagged packets, MPLS Packets, packets from a different network type with a larger MTU), you may need to use the –snaplen flag to adjust snort to process larger packets)
Where to go from here
If you want to learn more about how to run the 2.9.9.x version of Snort, and how to install additional software to enhance a Snort system, see my series on installing Snort on Ubuntu. If you want to develop Snort plugins, please see my guide: Installing Snort++ Example Plugins.
I would love to get feedback from you about this guide. Recommendations, issues, or ideas, please contact me here.
Installing Snort++ in Ubuntu (Version 3.0 Alpha 4 build 239)
NOTE: this article is out of date and has been replaced with a newer article: Installing Snort++ (Snort 3 Alpha 4 build 245) in Ubuntu
The instructions below show how to install Snort 3 alpha 4 build 239 on Ubuntu. This install has been tested on Ubuntu 14 and 16, for both the x86 and x64 architectures. For an outdated Ubuntu 12 version of these instructions, please go here. Note that Snort 3 is Alpha software, and therefore has bugs and issues, and should be installed for testing purposes only (not on production systems).
Snort 3 Alpha 4 Build 239 was released on July 28, 2017, and this guide has been tested with that version (releases after this specific release may not follow the same steps). Generic build instructions, prerequisites, and detailed notes are available in the manual.
If you want a more in-depth explanation of the install steps, which are very similar to the 2.9.9.x version of Snort, as well as instructions on how to configure and enhance Snort’s functionality, see my series on installing Snort 2.9.9.x on Ubuntu.
So let’s get started. First we need to install all the Snort pre-requisites from the Ubuntu repositories:
sudo apt-get install -y build-essential autotools-dev libdumbnet-dev libluajit-5.1-dev libpcap-dev libpcre3-dev zlib1g-dev pkg-config libhwloc-dev cmake
Install the optional (recommended) software:
sudo apt-get install -y liblzma-dev openssl libssl-dev cpputest libsqlite3-dev
Install tools required for compiling the source from github:
sudo apt-get install -y libtool git autoconf
Install the DAQ pre-requisites:
sudo apt-get install -y bison flex
If you want to build the documentation as well (not really needed, unless you want it, usually about 700 MB of libraries):
sudo apt-get install -y asciidoc dblatex source-highlight
Next we will create a directory to save the downloaded tarball files:
mkdir ~/snort_src cd ~/snort_src
First and install safec for runtime bounds checks on certain legacy C-library calls (this is optional but recommended):
cd ~/snort_src wget http://downloads.sourceforge.net/project/safeclib/libsafec-10052013.tar.gz tar -xzvf libsafec-10052013.tar.gz cd libsafec-10052013 ./configure make sudo make install
One of the Snort recommended prerequisites is Hyperscan 4.4.0. From their webpage: “Hyperscan is a regular expression engine designed to offer high performance, the ability to match multiple expressions simultaneously and flexibility in scanning operation.” Hyperscan needs Ragel 6.9 and the Boost header libraries.
Install Ragel 6.10 from source:
cd ~/snort_src wget http://www.colm.net/files/ragel/ragel-6.10.tar.gz tar -xzvf ragel-6.10.tar.gz cd ragel-6.10 ./configure make sudo make install
Download the Boost 1.64 libraries, but do not install:
cd ~/snort_src wget https://dl.bintray.com/boostorg/release/1.64.0/source/boost_1_64_0.tar.gz tar -xvzf boost_1_64_0.tar.gz
Install Hyperscan 4.5.1 from source, referencing the location of the Boost source directory:
cd ~/snort_src wget https://github.com/01org/hyperscan/archive/v4.5.2.tar.gz tar -xvzf v4.5.2.tar.gz mkdir ~/snort_src/hyperscan-4.5.2-build cd hyperscan-4.5.2-build/ cmake -DCMAKE_INSTALL_PREFIX=/usr/local -DBOOST_ROOT=~/snort_src/boost_1_64_0/ ../hyperscan-4.5.2 make sudo make install
If you want to test that Hyperscan works, from the build directory, run:
cd ~/snort_src/hyperscan-4.5.2-build/ ./bin/unit-hyperscan
The unit tests will run (this takes a few minutes).
Download and install Data AcQuisition library (DAQ) from the Snort website (note that DAQ for Snort 3 is a different DAQ than for the 2.9.9.x series of Snort):
cd ~/snort_src wget https://www.snort.org/downloads/snortplus/daq-2.2.2.tar.gz tar -xvzf daq-2.2.2.tar.gz cd daq-2.2.2 ./configure make sudo make install
Run the following command to update shared libraries:
sudo ldconfig
Now we are ready to install Snort from source. This command downloads and installs the latest version of Snort 3 (currently 3.0.0 Alpha 4, build 239, but as the codebase is updated, you’ll get a newer version). If you want to specifically download the version used in this guide, use this URL instead with wget below: https://github.com/snortadmin/snort3/archive/BUILD_239.tar.gz.
If you want to install all the snort directories under a single directory, see the section at the bottom of this document titled Changing the install location of Snort. Here we choose to install the entire Snort directory structure to a single folder under /opt/:
cd ~/snort_src wget https://github.com/snortadmin/snort3/archive/master.tar.gz tar -xvzf master.tar.gz cd snort3-master/ autoreconf -isvf ./configure --prefix=/opt/snort make sudo make install
Since the Snort installation places the Snort binary at /opt/snort/bin/snort, it is common to create a symlink to /usr/sbin/snort:
sudo ln -s /opt/snort/bin/snort /usr/sbin/snort
Snort 3 requires a few environmental variables, we store them temporarily in the current session so we can continue working, and save them permanently to the ~/.bashrc file (you’ll need to do this for every user profile):
export LUA_PATH=/opt/snort/include/snort/lua/\?.lua\;\; export SNORT_LUA_PATH=/opt/snort/etc/snort sh -c "echo 'export LUA_PATH=/opt/snort/include/snort/lua/\?.lua\;\;' >> ~/.bashrc" sh -c "echo 'export SNORT_LUA_PATH=/opt/snort/etc/snort' >> ~/.bashrc"
to ensure that these two environmental variables are available when using sudo, we need to add them to the /etc/sudoers file:
sudo visudo
in the editor, add the following to to the bottom of the file:
Defaults env_keep += "LUA_PATH SNORT_LUA_PATH"
use ctrl-x to exit, save when prompted by pressing y, then press enter to save the file to /etc/sudoers.tmp (which will get copied automatically to /etc/sudoers).
The last step of our Snort installation is to test that the Snort Binary runs. Execute Snort with the -V flag, which causes Snort to print the current version. You should see output similar to the following:
user@snort3:~$ snort -V
,,_ -*> Snort++ <*-
o" )~ Version 3.0.0-a4 (Build 239) from 2.9.8-383
'''' By Martin Roesch & The Snort Team
http://snort.org/contact#team
Copyright (C) 2014-2017 Cisco and/or its affiliates. All rights reserved.
Copyright (C) 1998-2013 Sourcefire, Inc., et al.
Using DAQ version 2.2.2
Using libpcap version 1.7.4
Using LuaJIT version 2.0.4
Using PCRE version 8.38 2015-11-23
Using ZLIB version 1.2.8
Using LZMA version 5.1.0alpha
Using OpenSSL 1.0.2g 1 Mar 2016
Using Hyperscan version 4.5.2 2017-08-05
user@snort3:~$
A note on install locations:
When you install snort to /opt/snort, you get the following folder structure:
user@snort3x86:/opt/snort$ tree /opt/snort -L 3
/opt/snort
├── bin
│ ├── snort
│ ├── snort2lua
│ ├── u2boat
│ └── u2spewfoo
├── etc
│ └── snort
│ ├── file_magic.lua
│ ├── snort_defaults.lua
│ └── snort.lua
├── include
│ └── snort
│ ├── actions
│ ├── codecs
│ ├── daqs
│ ├── decompress
│ ├── detection
│ ├── events
│ ├── file_api
│ ├── flow
│ ├── framework
│ ├── hash
│ ├── log
│ ├── lua
│ ├── main
│ ├── managers
│ ├── mime
│ ├── packet_io
│ ├── profiler
│ ├── protocols
│ ├── pub_sub
│ ├── search_engines
│ ├── sfip
│ ├── stream
│ ├── time
│ └── utils
├── lib
│ ├── pkgconfig
│ │ └── snort.pc
│ └── snort
│ └── daqs
└── share
└── doc
└── snort
36 directories, 8 files
The /opt/snort/bin folder contains the following Snort binaries:
- snort : The Snort binary.
- snort2lua : Tool to convert a Snort 2.9.8.x configuration file into a 3.x configuration file. More notes here.
- u2boat : U2boat is a tool for converting unified2 files into different formats.
- u2spewfoo: U2SpewFoo is a lightweight tool for dumping the contents of unified2 files to stdout.
Additionally, the following folders are created / used:
- /opt/snort/bin : Binaries for Snort and supporting software.
- /opt/snort/etc/snort : The configuration files for Snort.
- /opt/snort/include/snort : All include files for Snort.
- /opt/snort/lib/pkgconfig : The pkgconfig file for Snort (compilation details for Snort).
- /opt/snort/share/doc/snort : The documentation for the installed version of Snort.
Changing the install location of Snort
If you would rather have all these folders install to a more normal location (/usr/local) , add ‑‑prefix=/usr/local/ to the ./configure command when preparing to build Snort. This will install all these folders under the path you choose. You also need to modify some of the other paths detailed above, so if you decide to install in that manner, you should follow the install instructions detailed in the Snort blog.
Snort Rules
Snort3 rules have more options than Snort 2 rules, and while the normal rules downloaded with PulledPork or manually will work, for testing you will probably want to download the set of community rules specificallycreated for snort3. You can manually download snort3 specific community rules from the snort website:
cd ~/snort_src/ wget https://www.snort.org/downloads/community/snort3-community-rules.tar.gz tar -xvzf snort3-community-rules.tar.gz cd snort3-community-rules sudo mkdir /opt/snort/etc/snort/rules sudo cp snort3-community.rules /opt/snort/etc/snort/rules/ sudo cp sid-msg.map /opt/snort/etc/snort/rules/
now test that snort can load these rules:
/opt/snort/bin/snort -c /opt/snort/etc/snort/snort.lua -R /opt/snort/etc/snort/rules/snort3-community.rules
your output should contain something similar:
Loading rules: Loading /opt/snort/etc/snort/rules/snort3-community.rules: Finished /opt/snort/etc/snort/rules/snort3-community.rules. Finished rules. -------------------------------------------------- rule counts total rules loaded: 3462 text rules: 3462 option chains: 3462 chain headers: 264 -------------------------------------------------- ...
you may want to run Snort with the following flags to detect issues: the warn-all and pedantic flags. From the Snort3 manual:
Warnings are not emitted unless –warn-* is specified. –warn-all enables all warnings, and –pedantic makes such warnings fatal
Installing OpenAppID
OpenAppID allows for the identification of application layer traffic. The Snort team has put together a package of detectors, with assistance from the community that you can download and install, called the Application Detector Package which needs to be installed. First download the OpenAppID detector package:
cd ~/snort_src/ wget https://www.snort.org/downloads/openappid/5759 -O OpenAppId-5759 tar -xzvf OpenAppId-5759 sudo cp -R odp /opt/snort/lib/
Now we need to edit our snort configuration file to point to this odp directory:
sudo vi /opt/snort/etc/snort/snort.lua
At line 113 (yours line number may be slightly different) you will see the appid= entry. You will want to add the app detector dir option here, pointing to the parent folder of the odf folder. It should look like this:
appid =
{
app_detector_dir = '/opt/snort/lib',
}
note that you must have four spaces (not a tab) for the indented line. Now we want to test the configuration file loads correctly:
/opt/snort/bin/snort -c /opt/snort/etc/snort/snort.lua --warn-all
you should see output similar to:
... Snort successfully validated the configuration (with 0 warnings). o")~ Snort exiting
Now to load Snort with the OpenAppID detectors, as well as all rules (we omit the pedantic flag, since the rules will throw flowbit warnings that are non fatal and can be ignored:)
/opt/snort/bin/snort -c /opt/snort/etc/snort/snort.lua -R /opt/snort/etc/snort/rules/snort3-community.rules --warn-all
Create a simple rule to test that OpenAppID is working correctly:
sudo touch /opt/snort/etc/snort/rules/local.rules sudo vi /opt/snort/etc/snort/rules/local.rules
with the following content:
alert tcp any any -> any any ( msg:"Facebook trafic Seen"; appids:"Facebook";sid:10000001; )
test to make sure the rule loads correctly:
/opt/snort/bin/snort -c /opt/snort/etc/snort/snort.lua -R /opt/snort/etc/snort/rules/local.rules --warn-all
You should see one rule loaded successfully. Now let’s run snort in detection mode on an interface (change eth0 below to match your interface name), printing alerts to the console:
sudo /opt/snort/bin/snort -c /opt/snort/etc/snort/snort.lua -R /opt/snort/etc/snort/rules/local.rules -i eth0 -A alert_fast -k none
the -k none flag tells Snort to ignore bad checksums. the Stream and Frag decoders will drop packets that have bad checksums, and the packets will not get processed by the OpenAppID detectors. By including this flag, we ensure that a packet with a bad checksum still gets processed. Now from another window on that computer (open a new terminal window or a second ssh session), use wget
to connect to facebook:
wget facebook.com
from the first console window you will see alerts output similar to the following:
08/05−19:13:45.451834 [∗∗] [1:10000001:0] ”Facebook trafic Seen” [∗∗] [Priority: 0] [AppID: Facebook] {TCP} 157.240.1.35:443 −> 10.0.0.104:33882
08/05−19:13:45.451842 [∗∗] [1:10000001:0] ”Facebook trafic Seen” [∗∗] [Priority: 0] [AppID: Facebook] {TCP} 10.0.0.104:33882 −> 157.240.1.35:443
use ctrl-c to stop Snort.
Note: if you are collecting packets with a larger MTU that the standard MTU for your adapter (VLAN tagged packets, MPLS Packets, packets from a different network type with a larger MTU), you may need to use the –snaplen flag to adjust snort to process larger packets)
Where to go from here
If you want to learn more about how to run the 2.9.9.x version of Snort, and how to install additional software to enhance a Snort system, see my series on installing Snort on Ubuntu. If you want to develop Snort plugins, please see my guide: Installing Snort++ Example Plugins.
I would love to get feedback from you about this guide. Recommendations, issues, or ideas, please contact me here.
Installing Snort++ in Ubuntu (Version 3.0 Alpha 4 build 237)
NOTE: this article is out of date and has been replaced with a newer article: Installing Snort++ (Snort 3 Alpha 4 build 240) in Ubuntu
The instructions below show how to install Snort 3 alpha 4 build 237 on Ubuntu. This install has been tested on Ubuntu 14 and 16, for both the x86 and x64 architectures. For an outdated Ubuntu 12 version of these instructions, please go here. Note that Snort 3 is Alpha software, and therefore has bugs and issues, and should be installed for testing purposes only (not on production systems).
Snort 3 Alpha 4 Build 237 was released on July 13, 2017, and this guide has been tested with that version (releases after this specific release may not follow the same steps). Generic build instructions, prerequisites, and detailed notes are available in the manual.
If you want a more in-depth explanation of the install steps, which are very similar to the 2.9.9.x version of Snort, as well as instructions on how to configure and enhance Snort’s functionality, see my series on installing Snort 2.9.9.x on Ubuntu.
So let’s get started. First we need to install all the Snort pre-requisites from the Ubuntu repositories:
sudo apt-get install -y build-essential autotools-dev libdumbnet-dev libluajit-5.1-dev libpcap-dev libpcre3-dev zlib1g-dev pkg-config libhwloc-dev cmake
Install the optional (recommended) software:
sudo apt-get install -y liblzma-dev openssl libssl-dev cpputest cmake libsqlite3-dev
Install tools required for compiling the source from github:
sudo apt-get install -y libtool git autoconf
Install the DAQ pre-requisites:
sudo apt-get install -y bison flex
If you want to build the documentation as well (not really needed, unless you want it, usually about 700 MB of libraries):
sudo apt-get install -y asciidoc dblatex source-highlight
Next we will create a directory to save the downloaded tarball files:
mkdir ~/snort_src cd ~/snort_src
First and install safec for runtime bounds checks on certain legacy C-library calls (this is optional but recommended):
cd ~/snort_src wget http://downloads.sourceforge.net/project/safeclib/libsafec-10052013.tar.gz tar -xzvf libsafec-10052013.tar.gz cd libsafec-10052013 ./configure make sudo make install
One of the Snort recommended prerequisites is Hyperscan 4.4.0. From their webpage: “Hyperscan is a regular expression engine designed to offer high performance, the ability to match multiple expressions simultaneously and flexibility in scanning operation.” Hyperscan needs Ragel 6.9 and the Boost header libraries.
Install Ragel 6.10 from source:
cd ~/snort_src wget http://www.colm.net/files/ragel/ragel-6.10.tar.gz tar -xzvf ragel-6.10.tar.gz cd ragel-6.10 ./configure make sudo make install
Download the Boost 1.64 libraries, but do not install:
cd ~/snort_src wget https://dl.bintray.com/boostorg/release/1.64.0/source/boost_1_64_0.tar.gz tar -xvzf boost_1_64_0.tar.gz
Install Hyperscan 4.5.1 from source, referencing the location of the Boost source directory:
cd ~/snort_src wget https://github.com/01org/hyperscan/archive/v4.5.1.tar.gz tar -xvzf v4.5.1.tar.gz mkdir ~/snort_src/hyperscan-4.5.1-build cd hyperscan-4.5.1-build/ cmake -DCMAKE_INSTALL_PREFIX=/usr/local -DBOOST_ROOT=~/snort_src/boost_1_64_0/ ../hyperscan-4.5.1 make sudo make install
If you want to test that Hyperscan works, from the build directory, run:
cd ~/snort_src/hyperscan-4.5.1-build/ ./bin/unit-hyperscan
The unit tests will run (this takes a few minutes).
Download and install Data AcQuisition library (DAQ) from the Snort website (note that DAQ for Snort 3 is a different DAQ than for the 2.9.9.x series of Snort):
cd ~/snort_src wget https://www.snort.org/downloads/snortplus/daq-2.2.1.tar.gz tar -xvzf daq-2.2.1.tar.gz cd daq-2.2.1 ./configure make sudo make install
Run the following command to update shared libraries:
sudo ldconfig
Now we are ready to install Snort from source. This command downloads and installs the latest version of Snort 3 (currently 3.0.0 Alpha 4, build 237, but as the codebase is updated, you’ll get a newer version). If you want to specifically download the version used in this guide, use this URL instead with wget below: https://github.com/snortadmin/snort3/archive/3376324350b3ef6228c4e30799a22779413789c2.tar.gz.
If you want to install all the snort directories under a single directory, see the section at the bottom of this document titled Changing the install location of Snort. Here we choose to install the entire Snort directory structure to a single folder under /opt/:
cd ~/snort_src wget https://github.com/snortadmin/snort3/archive/master.tar.gz tar -xvzf master.tar.gz cd snort3-master/ autoreconf -isvf ./configure --prefix=/opt/snort make sudo make install
Since the Snort installation places the Snort binary at /opt/snort/bin/snort, it is common to create a symlink to /usr/sbin/snort:
sudo ln -s /opt/snort/bin/snort /usr/sbin/snort
Snort 3 requires a few environmental variables, we store them temporarily in the current session so we can continue working, and save them permanently to the ~/.bashrc file (you’ll need to do this for every user profile):
export LUA_PATH=/opt/snort/include/snort/lua/\?.lua\;\; export SNORT_LUA_PATH=/opt/snort/etc/snort sh -c "echo 'export LUA_PATH=/opt/snort/include/snort/lua/\?.lua\;\;' >> ~/.bashrc" sh -c "echo 'export SNORT_LUA_PATH=/opt/snort/etc/snort' >> ~/.bashrc"
to ensure that these two environmental variables are available when using sudo, we need to add them to the /etc/sudoers file:
sudo visudo
in the editor, add the following to to the bottom of the file:
Defaults env_keep += "LUA_PATH SNORT_LUA_PATH"
use ctrl-x to exit, save when prompted by pressing y, then press enter to save the file to /etc/sudoers.tmp (which will get copied automatically to /etc/sudoers).
The last step of our Snort installation is to test that the Snort Binary runs. Execute Snort with the -V flag, which causes Snort to print the current version. You should see output similar to the following:
user@snort3:~$ snort -V
,,_ -*> Snort++ <*-
o" )~ Version 3.0.0-a4 (Build 237) from 2.9.8-383
'''' By Martin Roesch & The Snort Team
http://snort.org/contact#team
Copyright (C) 2014-2017 Cisco and/or its affiliates. All rights reserved.
Copyright (C) 1998-2013 Sourcefire, Inc., et al.
Using DAQ version 2.2.1
Using libpcap version 1.7.4
Using LuaJIT version 2.0.4
Using PCRE version 8.38 2015-11-23
Using ZLIB version 1.2.8
Using LZMA version 5.1.0alpha
Using OpenSSL 1.0.2g 1 Mar 2016
Using Hyperscan version 4.5.1 2017-07-18
user@snort3:~$
Now let’s test snort with the default configuration file and ruleset:
user@snort3:~$ /opt/snort/bin/snort -c /opt/snort/etc/snort/snort.lua -R /opt/snort/etc/snort/sample.rules
--------------------------------------------------
o")~ Snort++ 3.0.0-a4-237
--------------------------------------------------
Loading /opt/snort/etc/snort/snort.lua:
ssh
pop
stream_tcp
gtp_inspect
stream_icmp
ftp_server
stream_udp
ips
http_inspect
wizard
file_id
ftp_data
smtp
back_orifice
port_scan
telnet
ssl
sip
rpc_decode
reputation
classifications
arp_spoof
appid
stream_user
stream_ip
stream
dnp3
ftp_client
references
dns
imap
stream_file
Finished /opt/snort/etc/snort/snort.lua.
Loading rules:
Loading /opt/snort/etc/snort/sample.rules:
Finished /opt/snort/etc/snort/sample.rules.
Finished rules.
--------------------------------------------------
rule counts
total rules loaded: 3974
text rules: 3974
option chains: 3974
chain headers: 187
--------------------------------------------------
port rule counts
tcp udp icmp ip
any 119 31 29 26
src 1685 4 0 0
dst 1927 232 0 0
both 0 1 0 0
total 3731 268 29 26
--------------------------------------------------
flowbits
defined: 124
not checked: 9
not set: 2
--------------------------------------------------
service rule counts - tcp to-srv to-cli
dcerpc: 3 0
drda: 3 0
ftp: 8 2
http: 1161 1553
ident: 1 0
imap: 29 1044
ircd: 1 1
ldap: 5 0
mysql: 29 1
netbios-ns: 4 0
netbios-ssn: 25 7
pop3: 12 1043
rtsp: 2 0
smtp: 550 3
ssl: 5 1
sunrpc: 9 0
telnet: 5 1
vnc-server: 1 3
total: 1853 3659
--------------------------------------------------
service rule counts - udp to-srv to-cli
dcerpc: 2 0
dns: 170 2
kerberos: 4 4
netbios-dgm: 7 7
netbios-ns: 1 1
netbios-ssn: 1 1
ntp: 1 0
snmp: 1 1
ssdp: 8 0
sunrpc: 7 3
tftp: 1 0
total: 203 19
--------------------------------------------------
fast pattern port groups src dst any
packet: 27 125 4
key: 23 107 1
header: 23 107 1
body: 0 2 0
file: 23 107 1
--------------------------------------------------
fast pattern service groups to-srv to-cli
packet: 29 17
key: 3 0
header: 1 3
body: 1 0
file: 1 4
--------------------------------------------------
search engine
instances: 565
patterns: 24659
pattern chars: 515569
num states: 409078
num match states: 23799
memory scale: MB
total memory: 10.6222
pattern memory: 1.43181
match list memory: 3.91914
transition memory: 5.20227
--------------------------------------------------
pcap DAQ configured to passive.
Snort successfully validated the configuration.
o")~ Snort exiting
user@snort3:~$
If you have output similar to the above, then Snort 3.0.0 Alpha 4 is installed and works.
A note on install locations:
When you install snort to /opt/snort, you get the following folder structure:
user@snort3x86:/opt/snort$ tree /opt/snort -L 3
/opt/snort
├── bin
│ ├── snort
│ ├── snort2lua
│ ├── u2boat
│ └── u2spewfoo
├── etc
│ └── snort
│ ├── file_magic.lua
│ ├── sample.rules
│ ├── snort_defaults.lua
│ └── snort.lua
├── include
│ └── snort
│ ├── actions
│ ├── codecs
│ ├── daqs
│ ├── decompress
│ ├── detection
│ ├── events
│ ├── file_api
│ ├── flow
│ ├── framework
│ ├── hash
│ ├── log
│ ├── lua
│ ├── main
│ ├── managers
│ ├── mime
│ ├── packet_io
│ ├── profiler
│ ├── protocols
│ ├── search_engines
│ ├── sfip
│ ├── stream
│ ├── time
│ └── utils
├── lib
│ ├── pkgconfig
│ │ └── snort.pc
│ └── snort
│ └── daqs
└── share
└── doc
└── snort
35 directories, 9 files
The /opt/snort/bin folder contains the following Snort binaries:
- snort : The Snort binary.
- snort2lua : Tool to convert a Snort 2.9.8.x configuration file into a 3.x configuration file. More notes here.
- u2boat : U2boat is a tool for converting unified2 files into different formats.
- u2spewfoo: U2SpewFoo is a lightweight tool for dumping the contents of unified2 files to stdout.
Additionally, the following folders are created / used:
- /opt/snort/bin : Binaries for Snort and supporting software.
- /opt/snort/etc/snort : The configuration files for Snort.
- /opt/snort/include/snort : All include files for Snort.
- /opt/snort/lib/pkgconfig : The pkgconfig file for Snort (compilation details for Snort).
- /opt/snort/share/doc/snort : The documentation for the installed version of Snort.
Changing the install location of Snort
If you would rather have all these folders install to a more normal location (/usr/local) , add ‑‑prefix=/usr/local/ to the ./configure command when preparing to build Snort. This will install all these folders under the path you choose. You also need to modify some of the other paths detailed above, so if you decide to install in that manner, you should follow the install instructions detailed in the Snort blog.
Where to go from here
If you want to learn more about how to run the 2.9.9.x version of Snort, and how to install additional software to enhance a Snort system, see my series on installing Snort on Ubuntu. If you want to work with protocol (layer 7) detection, please see my article on OpenAppID.
I would love to get feedback from you about this guide. Recommendations, issues, or ideas, please contact me here.
Snort 2.9.9.x on Ubuntu – Part 8: Conclusion
- Installing Snort
- Configuring Snort to Run as a NIDS
- Writing and Testing a Single Rule With Snort
- Installing Barnyard2
- Installing PulledPork
- Creating Upstart Scripts for Snort on Ubuntu 14
- Creating systemD Scripts for Snort on Ubuntu 16
- Installing BASE
- Conclusion
Where to Go From Here
I hope this series of articles has been helpful to you. Please feel free to provide feedback, both issues you experienced and recommendations that you have. The goal of this guide was not just for you to create a Snort NIDS, but to understand how all the parts work together, and get a deeper understanding of all the components, so that you can troubleshoot and modify your Snort NIDS with confidence.
Capturing More Traffic With Snort
You will probably want to configure your network infrastructure to mirror traffic meant for other hosts to your Snort sensor. This configuration is dependent on what network equipment you are using. If you are running Snort as a Virtual Machine on a VMware ESXi server, you can configure promiscuous mode for ESXi by following my instructions in this article: configure promiscuous mode for ESXi.
For different network infrastrucutre, you will need to do a little research to configure network mirroring for your Snort server. Cisco calls this a span port, but most other vendors call this Port Mirroring. Instructions for Mikrotik (a linux based switch and router product that I like). If you run DD-WRT, it can be configured with iptables, like any linux based system. If you have network equipment not listed above, any search engine should point you towards a solution, if one exists. Note that many consumer switches will not have the ability to mirror ports.
You can also purchase devices specifically made to mirror data (called taps). Some products that have been recommended on the Snort-Users list are:
More Advanced Snort Configuration
Snort has the ability to do much more than we’ve covered in this set of articles. Hopefully you’ve learned enough through this setup that you will be able to implement more advanced configurations and make Snort work for you. Some things that Snort is capable of:
- Multiple remote Snort sensors, for example on different subnets.
- The documentation section of the Snort website has a number of useful articles about more advanced things you can do with Snort.
Some other related articles I have written:
- Snort as a Network Intrusion Prevention System (NIPS).
- Installing Snort++ (Snort 3.0 Alpha).
- OpenAppID for Layer 7 protocol detection.
Recommended Reading
- Snort IDS and IPS Toolkit (Jay Beale’s Open Source Security)
(Kindle Version
) – This is a good book for understanding how Snort works under the hood. It is a little old, but is still relevent and very detailed.
- Snort Cookbook
– This book is very helpful in showing how Snort can be run to meet specific needs (using recipes that describe specific situations).
- Applied Network Security Monitoring: Collection, Detection, and Analysis
– I haven’t read this book, but it is well reviewed, and covers NIDS at a much higher level than the other two books.
Feedback
I would love to get feedback from you about this guide. Recommendations, issues, or ideas, please contact me here.
Snort 2.9.9.x on Ubuntu – Part 7: Installing BASE
- Installing Snort
- Configuring Snort to Run as a NIDS
- Writing and Testing a Single Rule With Snort
- Installing Barnyard2
- Installing PulledPork
- Creating Upstart Scripts for Snort on Ubuntu 14
- Creating systemD Scripts for Snort on Ubuntu 16
- Installing BASE
- Conclusion
Installing BASE On Ubuntu
BASE is a simple web GUI for Snort. Alternate products include Snorby, Splunk, Sguil, AlienVault OSSIM, and any syslog server.
Splunk is a fantastic product, great for ingesting, collating, and parsing large data sets. Splunk is free to use (limited to 500 MB of data per day, which is a lot for a small shop). Sguil client is an application written in tcl/tk. Snorby is abandoned, and relies on old versions of many Ruby packages that makes documenting the installation difficult, and a constantly changing target.
I’ve chosen to use BASE in this guide because it’s simple to setup, simple to use, and works well for what it does. Both BASE and Snorby are abandoned projects, and while Snorby gives a nice web-2.0 interface, since it is written in Ruby-on-Rails, the Ruby packages it relies on are constantly upgrading, which causes compatibility issues with other required Snorby packages, which causes too many installation problems. If you want to try installing Snorby, please see these unsupported out of date guides for Ubuntu 14 or Ubuntu 16.
There is a slight difference between BASE on Ubuntu 14 versus 16: BASE requires PHP 5, which isn’t available in the Ubuntu 16 archives (Ubuntu has moved on to PHP 7 in this release), so we have to use a PPA on Ubuntu 16 to install the php 5 packages:
# Ubuntu 16 only: sudo add-apt-repository ppa:ondrej/php sudo apt-get update sudo apt-get install -y apache2 libapache2-mod-php5.6 php5.6-mysql php5.6-cli php5.6 php5.6-common php5.6-gd php5.6-cli php-pear php5.6-xml
in Ubuntu 14, we can just install the necessary libraries:
# Ubuntu 14 only: sudo apt-get install -y apache2 libapache2-mod-php5 php5 php5-mysql php5-common php5-gd php5-cli php-pear
next install Pear image Graph:
sudo pear install -f --alldeps Image_Graph
Download and install ADODB:
cd ~/snort_src wget https://sourceforge.net/projects/adodb/files/adodb-php5-only/adodb-520-for-php5/adodb-5.20.8.tar.gz tar -xvzf adodb-5.20.8.tar.gz sudo mv adodb5 /var/adodb sudo chmod -R 755 /var/adodb
Download BASE and copy to apache root
cd ~/snort_src wget http://sourceforge.net/projects/secureideas/files/BASE/base-1.4.5/base-1.4.5.tar.gz tar xzvf base-1.4.5.tar.gz sudo mv base-1.4.5 /var/www/html/base/
Create the BASE configuration file:
cd /var/www/html/base sudo cp base_conf.php.dist base_conf.php
Now edit the config file:
sudo vi /var/www/html/base/base_conf.php
with the following settings (note that the trailing slash on line 80 is required, despite the instructions in the configuration file):
$BASE_urlpath = '/base'; # line 50 $DBlib_path = '/var/adodb/'; #line 80 $alert_dbname = 'snort'; # line 102 $alert_host = 'localhost'; $alert_port = ''; $alert_user = 'snort'; $alert_password = 'MySqlSNORTpassword'; # line 106
While in the base conf.php file, you will also want to comment out line 457 (we don’t want the DejaVuSans font), and un-comment (remove the two backslashes) from line 459, enabling a blank font. The section for fonts (begining at line 456) should look like this:
//$graph_font_name = "Verdana"; //$graph_font_name = "DejaVuSans"; //$graph_font_name = "Image_Graph_Font"; $graph_font_name = "";
Set permissions on the BASE folder, and since the password is in the base conf.php file, we should prevent other users from reading it:
sudo chown -R www-data:www-data /var/www/html/base sudo chmod o-r /var/www/html/base/base_conf.php
restart Apache:
sudo service apache2 restart
The last step to configure BASE is done via http:
- Browse to http://ServerIP/base/index.php and click on the setup page link (replace ServerIP with the IP of your Snort Server).
- Click on the Create BASE AG button on the upper right of the page.
- Click on the Main page link.
Note: If you read through the BASE configuration file, there are a number of other options you can implement if you like. A few options are SMTP Email alerts, IP Address to Country Support, and user authentication.
Congratulations, if you’ve made it this far, you have a fully-functioning Snort system. Please continue on to the Conclusion for more things you can do with Snort.
Snort 2.9.9.x on Ubuntu – Part 6b: Creating systemD Scripts for Snort on Ubuntu 16
- Installing Snort
- Configuring Snort to Run as a NIDS
- Writing and Testing a Single Rule With Snort
- Installing Barnyard2
- Installing PulledPork
- Creating Upstart Scripts for Snort on Ubuntu 14
- Creating systemD Scripts for Snort on Ubuntu 16
- Installing BASE
- Conclusion
Overview
In the previous articles in this series, we have created a complete Snort NIDS with a web interface and rulesets that automatically update. In this article, we will finalize the configuration of our Snort service by creating systemD scripts for the Snort and Barnyard2 daemons. If you are running Ubuntu 14, you should go see my Upstart article instead of this article.
Creating a systemD startup script in Ubuntu 16
Ubuntu 16 has moved to systemD for services / daemons. For more information about creating and managing systemD servcies, please see this excellent article.
To create the Snort systemD service, use an editor to create a service file:
sudo vi /lib/systemd/system/snort.service
with the following content (change ens160 if different on your system):
[Unit] Description=Snort NIDS Daemon After=syslog.target network.target [Service] Type=simple ExecStart=/usr/local/bin/snort -q -u snort -g snort -c /etc/snort/snort.conf -i ens160 [Install] WantedBy=multi-user.target
Now we tell systemD that the service should be started at boot:
sudo systemctl enable snort
And start the Snort service:
sudo systemctl start snort
Verify the service is running
systemctl status snort
Next, create the Barnyard2 systemd service. We will add two flags here: -D to run as a daemon, and -a /var/log/snort/archived logs, this will move logs that Barnyard2 has processed to the /var/log/snort/archived/ folder. Use an editor to create a service file:
sudo vi /lib/systemd/system/barnyard2.service
With the following content:
[Unit] Description=Barnyard2 Daemon After=syslog.target network.target [Service] Type=simple ExecStart=/usr/local/bin/barnyard2 -c /etc/snort/barnyard2.conf -d /var/log/snort -f snort.u2 -q -w /var/log/snort/barnyard2.waldo -g snort -u snort -D -a /var/log/snort/archived_logs [Install] WantedBy=multi-user.target
Now we tell systemD that the service should be started at boot:
sudo systemctl enable barnyard2
And start the barnyard2 service:
sudo systemctl start barnyard2
Verify the service is running
systemctl status barnyard2
Reboot the computer and check that both services are started
user@snortserver:~$ service snort status snort start/running, process 1116 user@snortserver:~$ service barnyard2 status barnyard2 start/running, process 1109 user@snortserver:~$
If both services are running, you are ready to move to the next section, where you will install BASE, a web-based GUI to view and profile alert data: Installing BASE
Snort 2.9.9.x on Ubuntu – Part 6a: Creating Upstart Scripts for Snort on Ubuntu 14
- Installing Snort
- Configuring Snort to Run as a NIDS
- Writing and Testing a Single Rule With Snort
- Installing Barnyard2
- Installing PulledPork
- Creating Upstart Scripts for Snort on Ubuntu 14
- Creating systemD Scripts for Snort on Ubuntu 16
- Installing BASE
- Conclusion
Overview
Creating the Upstart Scripts for Ubuntu 14
In the previous articles in this series, we have created a complete Snort NIDS with a web interface and rulesets that automatically update. In this article, we will finalize the configuration of our Snort service by creating Upstart scripts for the Snort and Barnyard2 daemons. If you are running Ubuntu 16, you should go see my systemD article instead of this article.
First create the Snort Upstart script:
sudo vi /etc/init/snort.conf
We will insert the below content into this Upstart script. Note that we are using the same flags that we used in earlier articles, so if Snort ran correctly for you earlier, then you shouldn’t need to change any of these flags:
description "Snort NIDS service"
stop on runlevel [!2345]
start on runlevel [2345]
script
exec /usr/sbin/snort -q -u snort -g snort -c /etc/snort/snort.conf -i eth0 -D
end script
Now make the script executable, and tell Upstart that the script exists:
sudo chmod +x /etc/init/snort.conf initctl list | grep snort snort stop/waiting
do the same for our Barnyard2 script:
sudo vi /etc/init/barnyard2.conf
with the following content:
description "barnyard2 service"
stop on runlevel [!2345]
start on runlevel [2345]
script
exec /usr/local/bin/barnyard2 -c /etc/snort/barnyard2.conf -d /var/log/snort -f snort.u2 -w /var/log/snort/barnyard2.waldo -g snort -u snort -D -a /var/log/snort/archived_logs
end script
Note that we have added a new flag here that we didn’t use before: -a /var/log/snort/archived_logs, this will move logs that Barnyard2 has processed to the /var/log/snort/archived_logs/ folder.
Now make the script executable, and tell Upstart that the script exists:
sudo chmod +x /etc/init/barnyard2.conf initctl list | grep barnyard barnyard2 stop/waiting
Reboot the computer and check that both services are started:
user@snortserver:~$ service snort status snort start/running, process 1116 user@snortserver:~$ service barnyard2 status barnyard2 start/running, process 1109 user@snortserver:~$
If both services are running, you are ready to move to the next section, where you will install BASE, a web-based GUI to view and profile alert data: Installing BASE
Snort 2.9.9.x on Ubuntu – Part 5: Installing PulledPork
- Installing Snort
- Configuring Snort to Run as a NIDS
- Writing and Testing a Single Rule With Snort
- Installing Barnyard2
- Installing PulledPork
- Creating Upstart Scripts for Snort on Ubuntu 14
- Creating systemD Scripts for Snort on Ubuntu 16
- Installing BASE
- Conclusion
Onwards
In the previous two sections of this article, we installed Snort and configured it to work as a NIDS with Barnyard2 processing packets that generated alerts based on a rule. In this article, we are going to install a Perl script called PulledPork, which will automatically download the latest rulesets from the Snort website.
Oinkcode
To download the main free ruleset from Snort, you need an oinkcode. Register on the Snort website and save your oinkcode before continuing, as the oinkcode is required for the most popular free ruleset.
Installing PulledPork
Install the PulledPork pre-requisites:
sudo apt-get install -y libcrypt-ssleay-perl liblwp-useragent-determined-perl
Download the latest PulledPork and install. Here we copy the actual perl file to /usr/local/bin and the needed configuration files to /etc/snort:
cd ~/snort_src wget https://github.com/shirkdog/pulledpork/archive/master.tar.gz -O pulledpork-master.tar.gz tar xzvf pulledpork-master.tar.gz cd pulledpork-master/ sudo cp pulledpork.pl /usr/local/bin sudo chmod +x /usr/local/bin/pulledpork.pl sudo cp etc/*.conf /etc/snort
Test that PulledPork runs by running the following command, looking for the output below:
user@snortserver:~$ /usr/local/bin/pulledpork.pl -V PulledPork v0.7.3 - Making signature updates great again! user@snortserver:~$
Now that we are sure that PulledPork works, we need to configure it:
sudo vi /etc/snort/pulledpork.conf
Make the following changes to the pulledpork.conf file. Anywhere you see ‹oinkcode› enter your oinkcode from the Snort website. I have included line numbers to help you identify the location of these lines in the configuration file.
Line 19: enter your oinkcode where appropriate (or comment out if no oinkcode) Line 29: Un-comment for Emerging threats ruleset (not tested with this guide) Line 74: change to: rule_path=/etc/snort/rules/snort.rules Line 89: change to: local_rules=/etc/snort/rules/local.rules Line 92: change to: sid_msg=/etc/snort/sid-msg.map Line 96: change to: sid_msg_version=2 Line 119: change to: config_path=/etc/snort/snort.conf Line 133: change to: distro=Ubuntu-12-04 Line 141: change to: black_list=/etc/snort/rules/iplists/black_list.rules Line 150: change to: IPRVersion=/etc/snort/rules/iplists
We want to run PulledPork once manually to make sure it works. We use the following flags:
-c /etc/snort/pulledpork.conf the location of the snort.conf file -l Write detailed logs to /var/log
Run the following command:
sudo /usr/local/bin/pulledpork.pl -c /etc/snort/pulledpork.conf -l
After this command runs (it takes some time), you should now see snort.rules in /etc/snort/rules, and .so rules in /usr/local/lib/snort_dynamicrules. Pulled Pork combines all the rulesets that it downloads into these two files. You need to make sure to add the line: include $RULE_PATH/snort.rules to the snort.conf file, or the pulled pork rules will never be read into memory when Snort starts:
sudo vi /etc/snort/snort.conf
Add the following line to enable snort to use the rules that PulledPork downloaded (line 547), after the line for local.rules:
include $RULE_PATH/snort.rules
Since we have modified snort.conf, we should test that Snort loads correctly in NIDS mode with the PulledPork rules included:
sudo snort -T -c /etc/snort/snort.conf -i eth0
Once that is successful, we want to test that Snort and Barnyard2 load correctly when run manually as daemons:
sudo /usr/local/bin/snort -u snort -g snort -c /etc/snort/snort.conf -i eth0 -D sudo barnyard2 -c /etc/snort/barnyard2.conf -d /var/log/snort -f snort.u2 -w /var/log/snort/barnyard2.waldo -g snort -u snort -D
As before, ping the IP address of the Snort eth0 interface, and then check the database for more events (remember to use the MYSQLSNORTPASSWORD):
mysql -u snort -p -D snort -e "select count(*) from event"
The number of events reported should be greater than what you saw the last time you ran this command. Now that we are sure that PulledPork runs correctly, we want to add PulledPork to root’s crontab to run daily:
sudo crontab -e
Choose any editor if prompted
The Snort team has asked you to randomize when PulledPork connects to their server to help with load balancing. In the example below, we have PulledPork checking at 04:01 every day. Change the minutes value (the 01 below) to a value between 0 and 59, and the hours value (the 04 below) to a value between 00 and 23. For more info on crontab layout, check here:
01 04 * * * /usr/local/bin/pulledpork.pl -c /etc/snort/pulledpork.conf -l
Stop the running daemons from earlier testing:
user@snortserver:~$ ps aux | grep snort snort 1296 0.0 2.1 297572 43988 ? Ssl 03:15 0:00 /usr/local/bin/snort -q -u snort -g snort -c /etc/snort/snort.conf -i eth0 -D user 1314 0.0 0.0 4444 824 pts/0 S+ 03:17 0:00 grep --color=auto snort user@snortserver:~$ sudo kill 1296 user@snortserver:~$ ps aux | grep barnyard2 snort 1298 0.0 2.1 297572 43988 ? Ssl 03:15 0:00 barnyard2 -c /etc/snort/barnyard2.conf -d /var/log/snort -f snort.u2 -w /var/log/snort/barnyard2.waldo -g snort -u snort -D user 1316 0.0 0.0 4444 824 pts/0 S+ 03:17 0:00 grep --color=auto barnyard2 user@snortserver:~$ sudo kill 1298
Note: Snort needs to be reloaded to see the new rules. This can be done with kill -SIGHUP snort-pid, or you can restart the snort service (once that’s created in a later part of this guide).
Additional note about shared object rules: In addition to regular rules, The above section will download Shared object rules. Shared object rules are also known as ”Shared Object rules”, ”SO rules”, ”pre-compiled rules”, or ”Shared Objects”. These are detection rules that are written in the Shared Object rule language, which is similar to C.
These rules are pre-compiled by the provider of the rules, and allow for more complicated rules, and allow for obfuscation of rules (say to detect attacks that haven’t been patched yet, but the vendor wants to allow detection without revealing the vulnerability). These rules are compiled by the vendor for specific systems. One of these systems is Ubuntu 12, and luckily these rules also work on Ubuntu 14 and 15.
Congratulations, if you have output similar to the above then you have successfully Configured PulledPork. Continue to the next section to install startup scripts for Snort and Barnyard2. Choose one of the two following links, depending on your version of Ubuntu. You will create an Upstart scripts for Ubuntu 12 and 14, and a systemD scripts for Ubuntu 15.
Choose One of the following to continue:
Ubuntu 14: Creating Upstart Scripts for Snort and Barnyard2
Ubuntu 16: Creating systemD Scripts for Snort