Apache MEMCACHED UDP Protection

Current a lot of sites blogging about memcached attacks on Servers here some details:

  • Memcached Servers need a installed and running Service called „memcached“
  • Websites need a php-plugin like php7.0-memcached to connect via API to the memcached Service
  • The Memcached Service uses a own Config File at debian /etc/memcached.conf
  • By default it MUST listen to localhost or socket
  • Admins MUST setup a FIREWALL like „ufw“ (iptables) and MUST check own Server for OPEN PORTS with nmap
  • The Problem is that Attackers can run Scripts against to your Server in a 10^6 Range like a BOTNET !! with ONE PC cause MEMCACHED supports this high count of REQUESTS without going down.

Test to open Port using nmap Port Scan with UDP Option NOT TCP:

sudo nmap -sU -p 11211 www.myserver.xyz

If the scan echo this YOU MUST check or install a FIREWALL!:
Host is up (0.10s latency).
11211/udp open|filtered unknown

if Echo shows this you are safe:
11211/udp filtered unknown

check your current Apache PHP Modules:

$sudo php -m

if memcached listed, the php api is active time to check more..

check for memcached service:

$sudo dpkg -l |grep mem

is memcached listed the service is installed, then do:
$sudo ps aux|grep mem

if the echo shows:
memcache ... /usr/bin/memcached -m 64 -p 11211 -u memcache -l -P /var/run/memcached/memcached.pid

the Service is active an listening..

Sample Config:

# memcached default config file
# 2003 - Jay Bonci <jaybonci@debian.org>
# This configuration file is read by the start-memcached script provided as
# part of the Debian GNU/Linux distribution.

# Run memcached as a daemon. This command is implied, and is not needed for the
# daemon to run. See the README.Debian that comes with this package for more
# information.

# Log memcached's output to /var/log/memcached
logfile /var/log/memcached.log

# Be verbose

# Be even more verbose (print client commands as well)

# Start with a cap of 64 megs of memory. It's reasonable, and the daemon default
# Note that the daemon will grow to this size, but does not start out holding this much
# memory
-m 128

# Default connection port is 11211
-p 11211

# Run the daemon as root. The start-memcached will default to running as root if no
# -u command is present in this config file
-u memcache

# Specify which IP address to listen on. The default is to listen on all IP addresses
# This parameter is one of the only security measures that memcached has, so make sure
# it's listening on a firewalled interface.

# Limit the number of simultaneous incoming connections. The daemon default is 1024
-c 300

# Lock down all paged memory. Consult with the README and homepage before you do this
# -k

# Return error when memory is exhausted (rather than removing items)

# Maximize core file limit
# -r

# Use a pidfile
-P /var/run/memcached/memcached.pid

Setup Firewall (ufw):

$sudo apt-get install ufw
$sudo ufw allow 80/tcp
$sudo ufw allow 443/tcp
$sudo ufw enable

Retest with NMAP Port Scan your OPEN Ports! Do this monthly! Cause sometimes the Firewall can have unknown Problems!!

Check the Memcached Log at /var/log/memcached.log for Events

Security: Webserver HTTPS with Self Signed Certificate Do it yourself in 5 Minutes!!

Today the Point of Security and encrypted Webserver Communication is rolling over every User who hosts own Websites on the Internet. Last decades HTTPS was only used by Online Login Pages like Shops and Banks to verify the Communication between a User PC and the Website. But after January 2015 the most Search Engines like google decides to force index of Websites with HTTPS Protocol. The Background is that a TLS encrypted Connection isn’t easy to track and to force „drive-by-load-Viruses“ to the Website Visitors.

Self Signed Certificate Sample
Self Signed Certificate Sample

But a lot of Webmasters of the Opensource Community were angry about this handling. Thats is not real problem if you won’t buy a SSL/TLS Certificate. Every Webmaster can create a self signed Certificate on his Webserver if he is able to login via ssh and to config the Webserver like Apache. Self signed Certificates are warned by the Webbrowsers at the only first view, but if the User wants to install the Certificate the Browser isn’t warning next visits!

The Search Engines like Google don’t check the trust of the Certificates by the robots and so your Site will be good placed on the Index like the last decades. The ONLY thing is that you MUST move all Files,Images, Internal Links and Bookmarks to „https://“  that the „LOCK“ of the Browser Dialog is „CLOSED“  and „GREEN“ like on the Picture .

Of course if you want, you can buy and install „Domain Name Trusted“ Certificates, but if you only host private Websites/Blogs you won’t really pay over 100$ per Year for the Certificates.


  • Secure Login to your Site/Blog
  • Encrypted Transfer of Data
  • Security for your Visitors
  • No Drive-BY-Loads
  • Less Content Stealing

You will remark next years that the internet will be moved to HTTPS!

To create a Certificate use „OPENSSL“ with this command,answere the Questions of the Script, later put the Certificates .crt and .key to /etc/ssl/.. and tell Apache to pull them there!

$sudo openssl req -x509 -nodes -days 365 -newkey rsa:2048 -keyout mysitename.key -out mysitename.crt