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Archive for October, 2010

DokuWiki and the the BeerWare License

2010/10/30 1 comment

I’m trying to do a better job of documenting the systems that make up InfoSanity. To do that it’s everyone’s favourite, a wiki. In this case I went with DokuWiki, for no real reason other than it came up first on a Google search. Installation is simple on a Debian based system, just the usual: apt-get install dokuwiki. So far so good, but I’m wondering how long I can actually keep the documentation upto date…

At the same time I came across the the BeerWare license from my Twitter feed (sorry, can’t find original message, thanks to whoever pointed me in the right direction. The license was created by Poul-Henning Kamp, and does a good job of summing up my feelings toward the tools/scripts I’ve released the last few years:

/*
 * ----------------------------------------------------------------------------
 * "THE BEER-WARE LICENSE" (Revision 42):
 * <phk@FreeBSD.ORG> wrote this file. As long as you retain this notice you
 * can do whatever you want with this stuff. If we meet some day, and you think
 * this stuff is worth it, you can buy me a beer in return Poul-Henning Kamp
 * ----------------------------------------------------------------------------
 */

So, why not combine the two together? DokuWiki has the ability to apply one of several standard licenses by default, but unfortunately BeerWare isn’t one of them. To correct this obvious mistake edit /etc/dokuwiki/license.php to include:

$license[‘beerware’] = array(
‘name’ => ‘Beerware License’,
‘url’  => ‘http://en.wikipedia.org/wiki/Beerware&#8217;,
);

n.b. I struggled to find a better license location that just deals with the license, if anyone finds better let me know.

Now it’s just a matter of editing the main dokuwiki config file, /etc/dokuwiki/dokuwiki.php:

$conf[‘license’] = ‘beerware’;

And Voila!

Dokuwiki showing the BeerWare License–Andrew Waite

Categories: Lab

SSH hardening with Breakinguard

2010/10/21 1 comment

As proven by the logs generated by Kippo honeypot sensors have shown, attacks against SSH services are regularly seen in the wild. Even if you follow best practices for securing the service, the malicious scans will utilise resources available to your environment; CPU, bandwidth etc. In sufficient volume legitimate operation may be impacted as the server rejects failed login attempts.

This is where utilities like Breakinguard come into their own. Basically Breakinguard monitors log files for signs of malicious activity, and once a single source has triggered enough alerts blocks all connections from the source location. Other utilities (most notably fail2ban) perform the same activities, but I’m partial to Breakinguard due to it’s small size and simple configuration (and from knowing the author 😉 ).

Installation is straightforward, and for the most part automated. Once downloaded and extracted installation is handled by the configure script. On Debian based systems this will install the pre-requisite Perl modules and transfer the utilities components to the standard locations:

  • breakinguard script – /usr/local/sbin/breakinguard
  • config – /etc/breakinguard.conf
  • init script – /etc/init.d/breakinguard

Once installed you need to edit your configuration. The breakinguard.conf file is fairly self explanatory, I normally edit:

  • $alert_email -> set to the email address that you want to receive notifications of blocked attacks. On a publicly accessible system these alerts can be high volume, you may want to use a specific email account or at least setup some auto-move rules in your email client to avoid your inbox being spammed.
  • $number_of_attempts -> This specifies the number of malicious log entries need to be generated by a specific IP address before the source is blocked. Due to the timing of the Breakinguard route this isn’t always an exact science, the default of 5 does a good job of avoid false positives whilst still blocking an attack in it’s infancy.
  • $log_to_watch -> selects the logfile to monitor for signs of malicious activity. /var/log/auth.log is the obvious choice on a Debian based system.
  • @safe_ips -> This array allows you to specify a number of trusted networks that will not be blocked, regardless of the number of times the they trigger alerts in the logs. This is useful for insuring that you don’t get locked out of your own systems in the event your keyboard ‘breaks’. On higher end systems with hardware remote management systems (iLo, DRAC, etc.) or virtual systems that provide remote access to the ‘physical’ console I leave this list to local subnet only and use the alternative options to access the server if I do lock myself out.
  • $DEBUG -> set to 1 by default, this runs the utility in test mode without actually blocking malicious sources, perfect for testing configuration before going live. Once you’re good to set set $DEBUG to 0 and wait for the attacks to start. Example testing in debug mode is below:
Breakinguard - Debug Mode

Breakinguard - Debug Mode

Blocking and unblocking of malicious sources is handled via iptables. Once the $number_of_attempts limit is hit Breakinguard will run the $block_command (configurable in /etc/breakinguard.conf) which by default is ‘/sbin/iptables -I INPUT -s %s -j DROP’, with %s being replaced with the attacking IP. After a configurable timeout ($block_length), the $unblock_command removes the restriction.

You can see the IP addresses currently blocked as they are listed in /var/run/breakinguard/, alternatively listing the current iptables configuration will show sources currently being blocked, for example:

Breakinguard iptables

Breakinguard iptables

Download Breakinguard here

–Andrew Waite

Categories: Honeypot, InfoSec, Kippo

Updating Dionaea

I’m sure this is basic for most of you, but I seem to keep making the same daft mistakes whilst updating Dionaea, so I’m hoping documenting the issues and corrections will work as a memory aid in the future.

Firstly, I can never remember Git’s equivalent to ‘svn update’, which is:

git pull

Next up is recompiling Dionaea from your updated source directory, this is no different to an initial install as per Markus’ excellent instructions.

I keep forgetting to update my configuration file to include any directives needed for the new shiny new functionality you’re upgrading to get access to. I find diff useful for identifying any new additions, for example

/opt/dionaea/etc/dionaea# diff dionaea.conf dionaea.conf.dist

Assuming there’s no major changes you should only see differences specific to your installation, for example your email address to receive analysis reports, or your VirusTotal api key. If there are any other differences you’ll need to add the new content.

From the experience I’ve had in the past week, if you encounter any unexpected problems after updating Dionaea, make sure your pre-requisites are also upto date. After updating Dionaea last week to gain access to the new integration with VirusTotal’s api my Dionaea sensor started to die randomly. Markus was a great help with troubleshooting (thanks again) and my problems were eventually corrected after it was noted that my libemu installation was outdated; after a quick ‘git pull’ and ‘make’ (again following Markus’ instructions).

As I said, this is probably basic for most of you out there, but as I keep making similar mistakes I plan to refer back to this list of daft issues before bugging anyone for support in future. You never know, it might allow someone else to retain an air of competence before proving otherwise 🙂

— Andrew

Categories: Dionaea, Honeypot

ToonCon

2010/10/09 1 comment

I’ve been lax in writing this, so apologises.ToonCon Logo

Recently the already vibrant social networking scene in Newcastle Upon Tyne gained another group, ToonCon. What is ToonCon?

 

ToonCON is a monthly meeting and yearly conference in Newcastle-upon-Tyne of people with an interest in information security, these people include security professionals, students and hobbyists. We attempt to meet once a month at a local venue in the heart of Newcastle city center to discuss information security, drink b33r and have a good time. Our chosen venue will have free WLAN access, be quiet enough to have a decent conversation, have wheelchair access and be safe enough to leave your new gadgets and laptops on the table. At this moment in time we are still deciding on a venue, if you know of one that fits the description above, let us know!

After two events, ToonCon has so far lived up to billing, with plenty of infosec debate on a whole range of topics. With attendee’s experience ranging from students who are still learning the ropes, to those who have been on the frontlines for many years, all are welcome and everyone has something to both offer and gain from the discussions.

If you’ve got an interest in keeping information secure (or accessing supposedly secure information) and in the North East why not get involved?

— Andrew Waite

Categories: ToonCon

gnuplotsql.py

Development of new features for Dionaea has been fairly impressive of late, and I’ve been lax in keeping up to date. When Markus asked if I’d tested the graph utility that he created and wrote about here, it served as a kick to stop putting off some of the jobs I’ve got on the growing to-do list.

I won’t go into too much detail about running the script as Markus has already done a better job than I could. However I will point out that if you run your Dionaea installation on Debian stable, then your out of luck; the standard packages for sqlite are too old to take the script. Best advice is to copy your logsql.sqlite database to a Ubuntu machine and work from there (oh, and in case you didn’t guess from the script name, make sure you’ve actually installed gnuplot…).

A powerful machine is recommended, the only Ubuntu system I had to hand whilst testing was my AA1 netbook, which took 85 minutes to crunch through the script and my database.

I have immediately found the graphs produced useful as they’ve highlighted a couple of obvious spikes (see below) in activity that I would have (and did) miss if solely relying on log files and databases. This really shows the power and importance of visualising security and log information.

dionaea-overview

dionaea-overview - from gnuplotsql.py

If you’re interested the output for the InfoSanity’s installation is now online here. I’m looking to expand the statistics from the InfoSanity honeypot environment that are publicly available, this makes a nice start. As always, big thanks to Markus and carnivore.it team for the effort.

— Andrew Waite

Categories: Dionaea, Honeypot, Tool-Kit