We’ve implemented a plugin to log failed login attempts to syslog, and a Fail2Ban filter for the same. If you run these on RedHat, you’ll need some additional configuration info… here it is:

^%(__prefix_line)sAuthentication failure for .* from <HOST>$

[[]client <HOST>[]] File does not exist: .*/~.*

[[]client <HOST>[]] (File does not exist|script not found or unable to stat): /\S*(\.php|\.asp|\.exe|\.pl)
[[]client <HOST>[]] script '/\S*(\.php|\.asp|\.exe|\.pl)\S*' not found or unable to stat *$

<HOST>\s.*\s.POST\s/xmlrpc.php*.\s.*

The post WordPress Fail2Ban RegEx for RedHat, CentOS, Amazon Linux appeared first on Chris Gilligan » new media.

Fail2Ban is a very efficient daemon that scans log files for malicious activity, and offers several options to ban offending IPs and hostnames. Although it is highly configurable, it requires a depth of knowledge beyond that required for GUI-accessible firewalls such as ConfigServer Security & Firewall.

Harden the Kernel

Before do anything further, it is necessary to harden the server at the kernel level. Doing so will prevent the majority of attacks that Fail2Ban config will have to deal with. Do this: Linux kernel sysctl hardening. Prior to learning those trix, I had solely relied upon ConfigServer Security and Firewall (CSF) to block malicious attacks. Heading those off at the kernel level is much more efficient.

I’m a huge fan of CSF, having used it with cPanel, Webmin and Virtualmin for many years. Moving to Amazon Web Services presented a challenge, however. I’ve yet to figure out how to use CSF on AWS, so I’ve backtracked to my old standby, Fail2Ban.

“Out of the box,” Fail2Ban for CentOS & other RedHat downstream distros only provides protection against SASL login failures. But with a little work and research, one can successfully configure many more “jails” for the malicious traffic. To take full advantage of Fail2Ban, the admin will need to become familiar with RegEx: regular expressions.

Amazon Web Services Security Groups

AWS provides several levels of firewall protection for EC2 instances; I mainly utilize EC2 security groups and VPC security groups. These firewalls serve to allow traffic to an instance based on IP address, IP block, port, etc. VPC will gateway traffic to and within a virtual cloud; one can create a security group for a cohort of replicated database servers to only allow traffic from within the virtual cloud. Likewise, one could create a cloud group with public facing, load-balanced Varnish reverse proxies that interact with an Apache or NginX app server, and that app server connects to the database cohort. The only publicly-accessible servers would be the web proxies. This is similar to what one might expect in a traditional network operations center.

Learn some RegEx

Learning a bit about RegEx will benefit the admin in virtually every programming endeavor: PHP, Perl, C, SQL etc. all make use of RegEx to match strings of text. Matching a variable string of text in a log file, for example, allows Fail2Ban to act upon that string, sending an email, looking up a hostname, and/or invoking a firewall rule to block traffic from the offending origin for a designated amount of time.

As stated earlier, plain vanilla Fail2Ban regex from EPEL is functional only to block SASL authentication errors. Most of the filters in the package are, at best, examples of what can be done, and will not function as written. Why? Because Fail2Ban has to deal with the particular implementations of log files in various GNU/Linux distributions, and the peculiarities of the reporting structure in those logs, no single RegEx, nor log file location, is going to work for every distribution. Neither can Fail2Ban account for every change in log file location or structure from version to version. What worked for Centos 5.x may not work for CentOS 6.x; what worked in kernel 2.8 may be invalid in kernel 3.4.

Also stated earlier, it is well worth the time to learn a little about RegEx. One vehicle to propel the admin far along the path is RegExr. Author Greg Skinner provides an online version as well as Adobe AIR standalone app. RegExr is an invaluable tool for writing and proofing regular expressions.

Write the RegEx

OK, here’s the payoff for reading so far: a regex filter that will squelch Dovecot brute force attacks on CentOS 6, Amazon Linux 2013 and other kernel 3.4 RedHat downstream distros such as Fedora and Arch. This would, of course go in /etc/fail2ban/filter.d/dovecot.conf:

Here’s the original, commented out via #:

#failregex = .*(?:pop3-login|dovecot):.*(?:Authentication failure|Aborted login \(auth failed|Aborted login \(tried to use disabled|Disconnected \(auth failed).*rip=(?P<host>\S*),.*

…and here’s a substitute, created via experimentation with RegExr:

failregex = .*auth.*pam.*dovecot.*(?:authentication failure).*rhost=<HOST>.*

How to create a valid RegEx to match the failures to ban? For that, one must monitor log files. In the case of Dovecot on Amazon Linux 2013, that would be /var/log/secure — same as it has ever been with RedHat downstreams. However, the logging is different than it may have been in CentOS 5.8.

Have a look at the log files: use grep to filter the secure log on “authentication failure”

tail -f -n 20000 /var/log/secure | grep "authentication failure"

There will likely be log entries similar to the following:

Apr 19 05:22:19 vm5 auth: pam_unix(dovecot:auth): authentication failure; logname= uid=0 euid=0 tty=dovecot ruser=oracle rhost=80.255.3.104 
Apr 19 05:22:20 vm5 auth: pam_unix(dovecot:auth): authentication failure; logname= uid=0 euid=0 tty=dovecot ruser=sybase rhost=80.255.3.104 
Apr 19 05:22:20 vm5 auth: pam_unix(dovecot:auth): authentication failure; logname= uid=0 euid=0 tty=dovecot ruser=informix rhost=80.255.3.104

RegEx mentioned previously will match those entries, and via Fail2Ban: BAN the offending IPs.

So, you think you’re ready with RegEx fu to tackle the Local Jail (jail.local)? Not so fast. Don’t use regex in jail.local. This file takes wild cards, not regex… so if you want to monitor all users’ /home/user/logs/access_log — you must wildcard /home/*/logs/access_log . NOT /home/.*/logs !

… more to come: follow this post for more details!

• WordPress RegEx
• Akismet Spam Logging & Fail2Ban

The post Fail2Ban Regex for RedHat, Fedora, CentOS and Amazon Linux 2013 appeared first on Chris Gilligan » new media.

phpMyAdmin database display

I recently ran into a problem with the upgraded 3.5.2 phpMyAdmin package provided via the rpmforge.repo. Search no longer works, nor does pagination, etc. Plus, it’s out of date and vulnerable to an XSS exploit.

I have solved this by changing to the EPEL repo, which maintains the latest version of phpMyAdmin.

This post will teach you how to install phpMyAdmin on CentOS, Amazon Linux, or Redhat. Configuration instructions are provided for Apache and NginX web servers.

For this to work properly and safely, you should be running SSL on your host. Otherwise, change the ForceSSL line in the config file provided below…

Install phpMyAdmin from EPEL repository

Uninstall current PMA:
yum erase phpMyAdmin

Set up EPEL repo:

Find the latest epel-release at http://download.fedoraproject.org/pub/epel/6/x86_64/
rpm -Uvh http://download.fedoraproject.org/pub/epel/6/x86_64/epel-release-6-8.noarch.rpm

On Amazon Linux, epel-release is already loaded. Edit /etc/yum.repos.d/epel.repo to enabled=1

Edit /etc/yum.repos.d/epel.repo to only include necessary software packages:
includepkgs=phpMyAdmin php-php-gettext

I have removed RPMforge repo due to some recent problems, but if you still need rpm forge repo:
exclude=phpMyAdmin php-php-gettext

Install PMA:
yum install phpMyAdmin

# phpMyAdmin - Web based MySQL browser written in php
# 
# Allows only localhost by default
#
# But allowing phpMyAdmin to anyone other than localhost should be considered
# dangerous unless properly secured by SSL

Alias /phpMyAdmin /usr/share/phpMyAdmin
Alias /phpmyadmin /usr/share/phpMyAdmin

<Directory /usr/share/phpMyAdmin/>
   <IfModule mod_authz_core.c>
     # Apache 2.4
     <RequireAny>
       Require ip 127.0.0.1
       Require ip ::1
     </RequireAny>
   </IfModule>
   <IfModule !mod_authz_core.c>
     # Apache 2.2
     Order Deny,Allow
     # comment out Allow from All and add your own static IPs here for security 
     # Allow from All
     Allow from 123.456.7.89
     Allow from 12.345.67.89
     Allow from 127.0.0.1
     Allow from ::1
   </IfModule>
</Directory>

<Directory /usr/share/phpMyAdmin/setup/>
   <IfModule mod_authz_core.c>
     # Apache 2.4
     <RequireAny>
       Require ip 127.0.0.1
       Require ip ::1
     </RequireAny>
   </IfModule>
   <IfModule !mod_authz_core.c>
     # Apache 2.2
     Order Deny,Allow
     Deny from All
     Allow from 127.0.0.1
     Allow from ::1
   </IfModule>
</Directory>

# These directories do not require access over HTTP - taken from the original
# phpMyAdmin upstream tarball
#
<Directory /usr/share/phpMyAdmin/libraries/>
    Order Deny,Allow
    Deny from All
    Allow from None
</Directory>

<Directory /usr/share/phpMyAdmin/setup/lib/>
    Order Deny,Allow
    Deny from All
    Allow from None
</Directory>

<Directory /usr/share/phpMyAdmin/setup/frames/>
    Order Deny,Allow
    Deny from All
    Allow from None
</Directory>

# This configuration prevents mod_security at phpMyAdmin directories from
# filtering SQL etc.  This may break your mod_security implementation.
#
#<IfModule mod_security.c>
#    <Directory /usr/share/phpMyAdmin/>
#        SecRuleInheritance Off
#    </Directory>
#</IfModule>

       location /phpMyAdmin {
               root /usr/share/;
               index index.php;
               location ~ ^/phpMyAdmin/(.+\.php)$ {
                       try_files $uri =404;
                       root /usr/share/;
                       fastcgi_pass localhost:9002;
                       fastcgi_param HTTPS on;
                       fastcgi_index index.php;
                       fastcgi_param SCRIPT_FILENAME /usr/share$fastcgi_script_name;
                       include /etc/nginx/fastcgi_params;
                       fastcgi_buffer_size 128k;
                       fastcgi_buffers 256 4k;
                       fastcgi_busy_buffers_size 256k;
                       fastcgi_temp_file_write_size 256k;
                       fastcgi_intercept_errors on;
               }
               location ~* ^/phpMyAdmin/(.+\.(jpg|jpeg|gif|css|png|js|ico|html|xml|txt))$ {
                       root /usr/share/;
               }
        }

        location /phpmyadmin {
               rewrite ^/* /phpMyAdmin last;
        }

<?php
/* Servers configuration */
$i = 0;

/* Server: MySQL Server [1] */
$i++;
$cfg['Servers'][$i]['verbose'] = 'MySQL Server';
$cfg['Servers'][$i]['host'] = '122.34.567.89';
$cfg['Servers'][$i]['port'] = '3306';
$cfg['Servers'][$i]['socket'] = '';
$cfg['Servers'][$i]['connect_type'] = 'tcp';
$cfg['Servers'][$i]['extension'] = 'mysqli';
$cfg['Servers'][$i]['auth_type'] = 'http';
$cfg['Servers'][$i]['user'] = 'pma';
$cfg['Servers'][$i]['password'] = '';
$cfg['Servers'][$i]['pmadb'] = 'phpmyadmin';
$cfg['Servers'][$i]['controluser'] = 'pma';
$cfg['Servers'][$i]['controlpass'] = 'pmapassword';
$cfg['Servers'][$i]['bookmarktable'] = 'pma_bookmark';
$cfg['Servers'][$i]['relation'] = 'pma_relation';
$cfg['Servers'][$i]['userconfig'] = 'pma_userconfig';
$cfg['Servers'][$i]['table_info'] = 'pma_table_info';
$cfg['Servers'][$i]['column_info'] = 'pma_column_info';
$cfg['Servers'][$i]['history'] = 'pma_history';
$cfg['Servers'][$i]['recent'] = 'pma_recent';
$cfg['Servers'][$i]['table_uiprefs'] = 'pma_table_uiprefs';
$cfg['Servers'][$i]['tracking'] = 'pma_tracking';
$cfg['Servers'][$i]['table_coords'] = 'pma_table_coords';
$cfg['Servers'][$i]['pdf_pages'] = 'pma_pdf_pages';
$cfg['Servers'][$i]['designer_coords'] = 'pma_designer_coords';

/* End of servers configuration */

$cfg['UploadDir'] = '/tmp';
$cfg['SaveDir'] = '/tmp';
/* only if your host supports SSL */
$cfg['ForceSSL'] = true;
$cfg['DefaultLang'] = 'en';
$cfg['ServerDefault'] = 1;
?>

Look in phpMyAdmin folder /usr/share/phpMyAdmin/examples for create_tables.sql

ssh to server as root user
mysql
-- or if it asks for password --
mysql -u your-mysql-superuser -pyour-superuser-password
mysql > source /usr/share/phpMyAdmin/examples/create_tables.sql


Log in to PMA

Now you can log into PMA with your mysql root user credentials. https://yourhost.tld/phpmyadmin

• Create a mysql user, pma, with the password you added to the config file, with no default permissions, on localhost
• Give pma user all permissions on phpmyadmin database, on localhost

Now you have a secure PMA which will work for all mysql users on your host. Version 3.5+ now has Status Monitoring and Advisor. Used in conjunction with a performance tuning script like MySQL Tuning Primer, it will help you fine-tune your MySQL server to your requirements and your environment.

phpMyAdmin MySQL server dashboard

The post Install phpMyAdmin with SSL on CentOS, Amazon Linux, RedHat (Apache or NginX) appeared first on Chris Gilligan » new media.

Trawire.com offers portable 4G MiFi and iPad rentals for visitors traveling to Iceland. Trawire’s CIO approached me for assistance after his systems administrator bailed and left him with a poorly maintained, self-hosted MacMini server running unoptimized WordPress installs.

Trawire website

I migrated the site to Amazon Web Services, where it now can handle traffic spikes and can be scaled and built out more easily, should the concept grow to additional markets. Working with my WordPress coding contacts in India, Trawire developed plugins to add features, and keep the software up-to-date. My contributions: caching and content distribution for static assets & queries, Virtualmin and phpMyAdmin for ease of management and development.

The post Portable Wifi Hotspot Rental Site appeared first on Chris Gilligan » new media.

I recently upgraded my WordPress theme to WooThemes Canvas 5.x, and I found that some of the icons were not rendering, but were showing a letter or integer instead. I dug into the code and found that these icons are now delivered via @font-face webfonts.

Meanwhile, I’m working on a client’s e-commerce site with Google WebFonts and a custom webfont to display the Rupee symbol (Indian currency).

Though the fonts were uploading properly to the CloudFront CDN, and were properly referenced in the minified CSS on the CDN, they were not rendering in Firefox or IE, and the SSL pages on the client’s site were throwing security warnings.

At first I thought this might be a W3 Total Cache issue, because upgrading to the latest development release had solved some other CSS issues. However, it turned out to be a browser security issue.

Evidently this is a security measure to prevent cross-site attacks, but you can allow this via Apache mod_headers, to allow your specific CloudFront (or other) domain, specified in the .htaccess file.

Some sites have suggested using “*” wildcards to allow all domains… but obviously this is a security issue: with this Header, you are granting JavaScript clients basic access to your resources. I recommend you only allow access to the specific CDN domains you require. Do this with a comma separated list, in double quotes.

# BEGIN CDN Cross-Site for Webfonts
<IfModule mod_mime.c>
        AddType font/ttf .ttf
        AddType font/eot .eot
        AddType font/opentype .otf
        AddType font/x-woff .woff
</IfModule>
<FilesMatch "\.(svg|ttf|otf|eot|woff)$">
    <IfModule mod_headers.c>
        Header set Access-Control-Allow-Origin "fonts.googleapis.com,{{yourdistro69}}.cloudfront.net"
    </IfModule>
</FilesMatch>
# END CDN Cross-Site for Webfonts

Yay! Delicious webfonts, even on SSL pages via CDN!

The post SSL and CloudFront CDN Support for WebFonts via .htaccess appeared first on Chris Gilligan » new media.

I have been working on a Varnish front-end for Apache, to be used with WordPress sites. I described the architecture in Load Balancing Virtualmin WordPress Hosting Server with Varnish on AWS. I now have a configuration that seems to work for all WordPress features, including logged-out commenting. This configuration also works well with W3 Total Cache.

This configuration is for Varnish on a separate server, but should also work on a single server with appropriate changes to the port and backend IP settings.

Varnish Config (/etc/sysconfig/varnish)

# Configuration file for varnish
#
# /etc/init.d/varnish expects the variable $DAEMON_OPTS to be set from this
# shell script fragment.
#
#
# Maximum number of open files (for ulimit -n)
NFILES=131072
#
# Locked shared memory (for ulimit -l)
# Default log size is 82MB + header
MEMLOCK=82000
#
# Maximum size of corefile (for ulimit -c). Default in Fedora is 0
# DAEMON_COREFILE_LIMIT="unlimited"
#
# Set this to 1 to make init script reload try to switch vcl without restart.
# To make this work, you need to set the following variables
# explicit: VARNISH_VCL_CONF, VARNISH_ADMIN_LISTEN_ADDRESS,
# VARNISH_ADMIN_LISTEN_PORT, VARNISH_SECRET_FILE
RELOAD_VCL=1
#
## Advanced configuration
#
# # Main configuration file.
VARNISH_VCL_CONF=/etc/varnish/wordpress-varnish3.vcl
#
# # Default address and port to bind to
# # Blank address means all IPv4 and IPv6 interfaces, otherwise specify
# # a host name, an IPv4 dotted quad, or an IPv6 address in brackets.
# VARNISH_LISTEN_ADDRESS=
VARNISH_LISTEN_PORT=80
#
# # Telnet admin interface listen address and port
VARNISH_ADMIN_LISTEN_ADDRESS=127.0.0.1
VARNISH_ADMIN_LISTEN_PORT=6082
#
# # Shared secret file for admin interface
VARNISH_SECRET_FILE=/etc/varnish/secret
#
# # The minimum number of worker threads to start
VARNISH_MIN_THREADS=1
#
# # The Maximum number of worker threads to start
VARNISH_MAX_THREADS=1000
#
# # Idle timeout for worker threads
VARNISH_THREAD_TIMEOUT=120
#
# # Cache file location if using file cache
#VARNISH_STORAGE_FILE=/var/lib/varnish/varnish_storage.bin
#
# # Cache size: in bytes, optionally using k / M / G / T suffix,
# # or in percentage of available disk space using the % suffix.
VARNISH_STORAGE_SIZE=3G
#
# # Backend storage specification
# malloc runs from RAM, file from file
VARNISH_STORAGE="malloc,${VARNISH_STORAGE_SIZE}"
#VARNISH_STORAGE="file,${VARNISH_STORAGE_FILE},${VARNISH_STORAGE_SIZE}"
#
# # Default TTL used when the backend does not specify one
VARNISH_TTL=120
#
# # DAEMON_OPTS is used by the init script. If you add or remove options,
# # be sure you update this section, too.
DAEMON_OPTS="-a ${VARNISH_LISTEN_ADDRESS}:${VARNISH_LISTEN_PORT} \
-f ${VARNISH_VCL_CONF} \
-T ${VARNISH_ADMIN_LISTEN_ADDRESS}:${VARNISH_ADMIN_LISTEN_PORT} \
-t ${VARNISH_TTL} \
-w ${VARNISH_MIN_THREADS},${VARNISH_MAX_THREADS},${VARNISH_THREAD_TIMEOUT} \
-u varnish -g varnish \
-S ${VARNISH_SECRET_FILE} \
-s ${VARNISH_STORAGE}"
#

Varnish VCL (/etc/varnish/wordpress-varnish3.vcl)

backend origin {
.host = "10.11.12.13";
.port = "80";
.connect_timeout = 60s;
.first_byte_timeout = 60s;
.between_bytes_timeout = 60s;
}
#
sub vcl_recv {
# only using one backend
set req.backend = origin;
#
# set standard proxied ip header for getting original remote address
set req.http.X-Forwarded-For = client.ip;
#
# logged in users must always pass
if( req.url ~ "^/wp-(login|admin)" || req.http.Cookie ~ "wordpress_logged_in_" ){
return (pass);
}
# accept purges from w3tc and varnish http purge
if (req.request == "PURGE") {
return (lookup);
}
#
# don't cache search results
if( req.url ~ "\?s=" ){
return (pass);
}
#
# always pass through posted requests and those with basic auth
if ( req.request == "POST" || req.http.Authorization ) {
return (pass);
}
#
# else ok to fetch a cached page
unset req.http.Cookie;
return (lookup);
}
#
# accept purges from w3tc and varnish http purge
sub vcl_hit {
if (req.request == "PURGE") { purge; }
return (deliver);
}
#
# accept purges from w3tc and varnish http purge
sub vcl_miss {
if (req.request == "PURGE") { purge; }
return (fetch);
}
#
sub vcl_fetch {
#
# remove some headers we never want to see
unset beresp.http.Server;
unset beresp.http.X-Powered-By;
#
# only allow cookies to be set if we're in admin area - i.e. commenters stay logged out
if( beresp.http.Set-Cookie && req.url !~ "^/wp-(login|admin)" ){
unset beresp.http.Set-Cookie;
}
#
# don't cache response to posted requests or those with basic auth
if ( req.request == "POST" || req.http.Authorization ) {
return (hit_for_pass);
}
#
# only cache status ok
if ( beresp.status != 200 ) {
return (hit_for_pass);
}
#
# don't cache search results
if( req.url ~ "\?s=" ){
return (hit_for_pass);
}
#
# else ok to cache the response
set beresp.ttl = 24h;
return (deliver);
}
#
sub vcl_deliver {
# add debugging headers, so we can see what's cached
if (obj.hits > 0) {
set resp.http.X-Cache = "HIT";
}
else {
set resp.http.X-Cache = "MISS";
}
# remove some headers added by varnish
unset resp.http.Via;
unset resp.http.X-Varnish;
}
#
sub vcl_hash {
hash_data( req.url );
# altering hash so subdomains are ignored.
# don't do this if you actually run different sites on different subdomains
if ( req.http.host ) {
hash_data( regsub( req.http.host, "^([^\.]+\.)+([a-z]+)$", "\1\2" ) );
} else {
hash_data( server.ip );
}
# ensure separate cache for mobile clients (WPTouch workaround)
if( req.http.User-Agent ~ "(iPod|iPhone|incognito|webmate|dream|CUPCAKE|WebOS|blackberry9\d\d\d)" ){
hash_data("touch");
}
return (hash);
}

The post Varnish VCL and Config for WordPress with W3 Total Cache appeared first on Chris Gilligan » new media.