Fail2ban
From CVL Wiki
(→Installing Fail2ban) |
(→Installing Fail2ban) |
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# Download the latest official source tarball: http://www.fail2ban.org/wiki/index.php/Downloads | # Download the latest official source tarball: http://www.fail2ban.org/wiki/index.php/Downloads | ||
# Unpack by double clicking or command line | # Unpack by double clicking or command line | ||
− | + | tar xvfj fail2ban-0.8.14.tar.bz2 | |
# Go into the folder and run the following command to install Fail2ban | # Go into the folder and run the following command to install Fail2ban | ||
− | + | cd fail2ban-0.8.14 | |
− | + | sudo python setup.py install | |
# Copy the init scipt to the launchdaemon directory | # Copy the init scipt to the launchdaemon directory | ||
− | + | sudo cp files/macosx-initd /Library/LaunchDaemons/org.fail2ban.plist | |
# Open the org.fail2ban.plist and delete the first two lines, such that the first line starts with ''<?xml ...'' | # Open the org.fail2ban.plist and delete the first two lines, such that the first line starts with ''<?xml ...'' | ||
− | + | sudo nano /Library/LaunchDaemons/org.fail2ban.plist | |
# Make a log file and give it proper permissions | # Make a log file and give it proper permissions | ||
− | + | sudo touch /var/log/fail2ban.log | |
− | + | sudo chgrp admin /var/log/fail2ban.log | |
# Add these two lines to /etc/pf.conf | # Add these two lines to /etc/pf.conf | ||
− | + | table <fail2ban> persist | |
− | + | block drop log quick from <fail2ban> to any | |
# | # | ||
Revision as of 15:46, 9 January 2015
Contents |
Fail2ban
We use the package fail2ban on all of our linux machines to help prevent ssh password brute-forcing. This package will block an IP address after a certain number (usually 10) of failed attempts.
Removing Fail2ban Block
If your address has been accidentally blocked on a server, and you are able to log in and control the server (usually via a different computer) you can remove your banned IP address from iptables.
To unban an IP address manually, it is necessary to know the chain name and the rule number. The following command can be used to acquire this information:
Code:
iptables -L -n --line-numbers
The relevant bits are at the end of the output. Here is an example chain with attendant rules:
Code:
Chain fail2ban-ssh (1 references) num target prot opt source destination 1 DROP all -- 204.110.13.107 anywhere 2 DROP all -- 1.234.20.21 anywhere 3 DROP all -- gw-tair-rp.rel.com.ua anywhere 4 RETURN all -- anywhere anywhere
In this example, three (3) IP addresses have been banned via the SSH jail (these are the DROP rules).
To unban an IP address, you would run the following command:
Code:
iptables -D [chain-name] [line-number]
To unban the IP address 1.234.20.21 (see above), the command would be:
Code:
iptables -D fail2ban-ssh 2
Reference: http://www.howtoforge.com/forums/showthread.php?t=51366&page=2
Installing Fail2ban
OS X
This is an advanced setup, and requires using the terminal to install and modify files.
- Download the latest official source tarball: http://www.fail2ban.org/wiki/index.php/Downloads
- Unpack by double clicking or command line
tar xvfj fail2ban-0.8.14.tar.bz2
- Go into the folder and run the following command to install Fail2ban
cd fail2ban-0.8.14 sudo python setup.py install
- Copy the init scipt to the launchdaemon directory
sudo cp files/macosx-initd /Library/LaunchDaemons/org.fail2ban.plist
- Open the org.fail2ban.plist and delete the first two lines, such that the first line starts with <?xml ...
sudo nano /Library/LaunchDaemons/org.fail2ban.plist
- Make a log file and give it proper permissions
sudo touch /var/log/fail2ban.log sudo chgrp admin /var/log/fail2ban.log
- Add these two lines to /etc/pf.conf
table <fail2ban> persist block drop log quick from <fail2ban> to any
Optional Installs
- Install IceFloor
- Install Xcode and MacPorts: https://guide.macports.org/chunked/installing.html
add the below line to /opt/local/etc/fail2ban/filters.d/ssh.conf
^%(__prefix_line)s(?:error: PAM: )?unknown user for illegal user .* from <HOST>( via \S+)?\s*$