Ips

Today the OISF development team released 0.8.2 of the Suricata IDS/IPS engine. I feel this is definitely the best release so far. Read the announcement here. In short, stability was improved, memory footprint reduced, performance improved and new features were added. One of the tools we used to help improve the engine is a fuzzer created by Will Metcalf, our QA lead. In short, the script takes a pcap file, runs it through editcap (part of wireshark) altering a number of random bytes, then feeds the altered pcap file to Suricata. This resulted in many interesting corner cases. Naturally the script makes sure you don’t forget to enable “ulimit -c unlimited” and such :) More on that script can be found on Will’s blog node5. ...

Yesterday the OISF development team released Suricata 0.8.1. This release is much improved from our December 31st release. It is way more stable, performs better and has more features. Thanks to the now included HTP library we have much better HTTP handling. The stream engine has seen massive improvements. Initial experimental CUDA code has been added. Initial Win32 support has been added. We’ve added number of missing rule keywords. Many bugs were fixed. ...

For over a year I’ve been working on a prototype implementation of a new IDS/IPS engine for the Open Infosec Foundation. This is not necessarily going to be the engine we’ll be using in OISF, although it’s likely that at least some of the code will be used. Discussions about features for the engine are still ongoing ( wiki, list), once that settles down we’ll see whats usable and whats not. In the worst case I still think many parts like hashing functions, pattern matcher implementations, protocol decoders, etc can be used. ...

This year there will be a lot of work that needs to be done for the Open Infosec Foundation. And like I wrote a few days ago, a lot of work is already being done. However, most of it is unpaid at this time as it will be some months before our funding comes in. So at least until then I’m available and looking for contract work. For the last two years I’ve been doing work as a contractor in the (open source) security field. My experience is mostly in coding in C and Perl, primarily on Snort and Snort_inline. Recently I created the (Perl language) SidReporter program for Emerging Threats. Areas I worked in: IPv6 IDS/IPS coding, signature writing, Web Application Firewalls, threading, bandwidth accounting, and more… ...

The year 2008 was an exciting year to me. The biggest thing going on the infosec side was the formation of the Open Infosec Foundation. We’ve been working on it behind the scenes for more than a year now, and it’s cool that we’ve finally announced our plans. Of course, the work is just getting started. Next year, we expect to finalize our foundation setup. We’re working with the Software Freedom Law Center for setting up the foundation charter and consortium rules. While the US government is funding us initially, we hope the consortium will guarantee our long term funding. We are talking to some interesting companies already, both big and small. ...

Last week Matt Jonkman announced the formation of the Open Infosec Foundation. This foundation has been grant funded to create a new open source IDS/IPS engine. Together with Will Metcalf and of course Matt himself, I will be working on this. We want this to be a real community effort where there is a role for everyone in the infosec community. Developers, admins, vendors, goverments, research, education, everyone. There is a lot of work ahead, but that should be great fun and very inspiring. So far things are interesting already. The discussion mailinglist is growing rapidly with many ppl from the community and industry. A #oisf IRC channel was created today on freenode. Join us there to participate in discussion about this project! ...

In Snort_inline’s stream4 modifications, one of the changes is that out of order TCP packets are treated differently from unmodified stream4. This can cause some new alerts to appear and some unexpected behaviour. So I’ll try to explain what happens here. First of all let me explain quickly what out of order packets are. To put it simple, TCP packets are send out by the source host in a specific order but can arrive in a different order at the destination. Packetloss, link saturation, routing issues are among many things that can cause this. A Snort_inline specific issue is that when Snort_inline can’t keep up with the packets it needs to process, it will drop packets which causes packetloss. These packets will then have to be resent by the sending host. ...

A few days ago I posted a blog article about stopping comment spam with ModSecurity using realtime blacklists (rbl). While the approach was working, I noted having problems with rules when I tried to match on POST methods in HTTP requests. Luckily, ModSecurity creator Ivan Ristic was quick to point out where the problem is. I’m using the Core Ruleset for ModSecurity, and one thing that ruleset does is use the ’lowercase’ transformation. This converts all text from arguments to lowercase, so my ^POST$ match would never be able to match. So like Ivan suggested, using ^post$ solved this part. ...

Spammers are known to use compromised hosts from all over the world to send their messages. Many people are blocking or scoring email spam based on realtime blacklist (rbl), which contain ipaddresses of these known bad hosts. In my experience this works fairly well for email. A while ago I noticed in the ModSecurity documentation for version 2.0 that ModSecurity features an operator called rbl, that can be used to check the ipaddress of a visitor with a rbl. So I decided to see if I could use the realtime blacklists to prevent comment spam on my blog. Turns out this works great! In this post I’ll show how to get it working.

This week SourceFire published a security advisory for (among others) Snort version 2.6.1.2, on which Snort_inline is based. So I took some time to update Snort_inline. Normally this would have taken Will and me quite some time, but since we switched to using svn those days are gone. I was able to update it in under a hour. I was very happy I blogged about the procedure to follow, since I had already forgotten about it ;-) ...