Czarism.com

Some steps in this document require priviledged access, and you'll want to limit access to the cert files to all but the root user. So you should su to root and create a working directory that only root has read/write access to (for example: mkdir certwork, chmod 600 certwork). Go to that directory.

Generate a server key:

openssl genrsa -des3 -out server.key 4096

Then create a certificate signing request with it. This command will prompt for a series of things (country, state or province, etc.). Make sure that "Common Name (eg, YOUR name)" matches the registered fully qualified domain name of your box (or your IP address if you don't have one). I also suggest not making a challenge password at this point, since it'll just mean more typing for you.

The default values for the questions ([AU], Internet Widgits Pty Ltd, etc.) are stored here: /etc/ssl/openssl.cnf. So if you've got a large number of certificate signing requests to process you probably want to carefully edit that file where appropriate. Otherwise, just execute the command below and type what needs to be typed:

openssl req -new -key server.key -out server.csr

Now sign the certificate signing request. This example lasts 365 days:

openssl x509 -req -days 365 -in server.csr -signkey server.key -out server.crt

Make a version of the server.key which doesn't need a password:

openssl rsa -in server.key -out server.key.insecure
mv server.key server.key.secure
mv server.key.insecure server.key

These files are quite sensitive and should be guarded for permissions very carefully. Chown them to root, if you're not already sudo'd to root. I've found that you can chmod 000 them. That is, root will always retain effective 600 (read) rights on everything.

Brute-force break-in attempts are quite frequent against an SSH server and other password protected internet-services (such as ftp,pop,...). Automated scripts try multiple combinations of username/password (brute-force, dictionary attack) and sometimes changing the port to something other than the default can't be done. Furthermore, scouring your log files yourself is not only time consuming, but can be difficult too.*

Fail2ban attempts to alleviate these issues by providing an automated way of not only identifying possible break-in attempts, but acting upon them quickly and easily in a user-definable manner.

Log files contain interesting information, especially about failed logins. This information can be used to ban an offensive host. This is exactly what Fail2ban does. It scans log files and detect patterns which correspond to possible breakin attempts and then performs actions. Most of the time, it consists of adding a new rule in a firewall chain and sending an e-mail notification to the system administrator.

Here is a list of the most important features available in Fail2ban:

• client/server
• multithreaded
• Gamin support
• autodetection of the date/time format
• wildcard support in logpath option
• support for a lot of services (sshd, apache, qmail, proftpd, sasl, etc)
• support for several actions (iptables, tcp-wrapper, shorewall, mail notifications, etc)

The code has been completely rewritten since 0.6.x. Fail2ban is entirely written in Python and thus should work on most of the *nix systems.

 

Fail2ban is composed of 2 parts: a client and a server. The server is multi-threaded and listens on a Unix socket for commands. The server itself knows nothing about the configuration files. Thus, at start-up, the server is in a "default" state in which no jails are defined. The following options are available for fail2ban-server:

-b                   start in background
-f                   start in foreground
-s <FILE>            socket path
-x                   force execution of the server
-h, --help           display this help message
-V, --version        print the version

fail2ban-server should not be used directly except in case of debugging. The option -s <FILE> is probably the most important one and is used to set the socket path. Thus, it is possible to run several instances of Fail2ban on different sockets. However, this should be not required because Fail2ban can run several jails concurrently.

If fail2ban-server crashes (does it?), it is possible that the socket file has not been removed correctly. The -x option tells the server to delete the socket file before start-up. If the socket file of a running server is removed, it is not possible to communicate with this server anymore.

The server handles the signals SIGTERM and SIGINT. When receiving one of these signals, fail2ban-server will quit nicely.

Client

fail2ban-client is the frontend of Fail2ban. It connects to the server socket file and sends commands in order to configure and operate the server. The client can read the configuration files or can simply be used to send a single command to the server using either the command line or the interactive mode (which is activated with the -i option). fail2ban-client can also start the server. The following options are available for fail2ban-client:

-c <DIR>                configuration directory
-s <FILE>               socket path
-d                      dump configuration. For debugging
-i                      interactive mode
-v                      increase verbosity
-q                      decrease verbosity
-x                      force execution of the server
-h, --help              display this help message
-V, --version           print the version

As for fail2ban-server, the option -s <FILE> can be used to set the socket path. Notice that this command line option overrides the socket option set in fail2ban.conf. The default configuration directory is /etc/fail2ban but can be override with the -c <DIR> option. The -x option is simply forwarded to fail2ban-server when starting the server.

A useful option for debugging is -d. This prints the configuration parsed by fail2ban-client. The output corresponds to the stream sent to the server. If the output of -d shows:

['set', 'loglevel', 1]
['set', 'logtarget', 'STDERR']

It is possible to achieve the same with:

$ fail2ban-client set loglevel 1
$ fail2ban-client set logtarget STDERR

Everything set in the configuration files can be configured manually. The configuration is just a simple and efficient way to configure the server. fail2ban-client only translates the configuration into a suite of commands. However, fail2ban-client has 2 more commands for its internal use. The first one is start. When typing:

$ fail2ban-client start

the client will first try to fork a server instance. The client then waits for the server to start-up by sending ping requests to it. Once the server responds to these requests, fail2ban-client parses the configuration and sends the corresponding commands to the server. The second one is reload. When typing:

$ fail2ban-client reload

the client will tell the server to stop all jails, parses the configuration files again and send the commands to the server. This is useful when a new configuration must be loaded without shutting down the server. This is also very useful when debugging the server. It is possible to start the server with fail2ban-server -f in one terminal and to load the configuration by typing fail2ban-client reload in an other one. Thus, client and server output will not be mixed up.

Any other commands are simply sent to the server without any specific treatment. However, most of the time, only the 2 above commands and stop will be used.

There is probably one last useful command: status [jail]. Without a jail name, the global status of the server is returned. If jail corresponds to an existing jail, the status of this jail is displayed.

A list with all commands is available here.

Welcome to the Basic Analysis and Security Engine (BASE) project

BASE is the Basic Analysis and Security Engine. It is based on the code from the Analysis Console for Intrusion Databases (ACID) project. This application provides a web front-end to query and analyze the alerts coming from a SNORT IDS system. BASE is a web interface to perform analysis of intrusions that snort has detected on your network. It uses a user authentication and role-base system, so that you as the security admin can decide what and how much information each user can see. It also has a simple to use, web-based setup program for people not comfortable with editing files directly. BASE is supported by a group of volunteers. They are available to answer any questions you may have or help you out in setting up your system. They are also skilled in intrusion detection systems and make use of that knowledge in the development of BASE.