Defense-in-Depth, Part 2: Advanced Intrusion Defense Joel Snyder Opus One

Traditional perimeter technology is being… … Supplemented?

A firewall is not just a firewall any more Firewalls now have “advanced application intelligence” Actually, they had that already, but the marketroids had to keep themselves busy Firewalls now are “intrusion prevention systems” Isn’t every firewall an intrusion prevention system? Firewalls now do virus scanning, content scanning, and ironing Application-layer firewalls are needed to protect legions of inadequate web programmers IDS has been replaced by IPS (No, I don’t believe that, I’m just repeating awful rumors) Worms now outnumber viruses in your by a factor of 20 to 1 Spam represents 50% to 75% of all you receive

Key question: Do you need this? Do you need to buy (or upgrade) to a bigger, smarter, faster, more capable firewall? Do you need to buy an IPS? …an application layer firewall? …a smarter IDS? …an SSL VPN device? Do I want an all-in-one thing? Do I want individual parts? The answer you’ve been waiting for… is on the very next slide!

Should I buy a lot of this new security stuff? And if I do buy this, what kind should I buy? And where should I put it? And which product should I buy? Answer: 42

I can’t tell you what is right for your network I can tell you what products are out there and what they are doing I can also tell you what the trends are in these products But the hard work remains yours So let’s look at what’s happening in the firewall business

March, 2004: Information Security sponsors research on new firewall technologies Products from Check Point, Cyberguard, NetScreen, Nortel Networks, Symantec, Secure Computing, Watchguard Support from Andy Briney, Neil Roiter at Information Security

Firewalls have been around for a very long time “[AT&T’s gateway creates] a sort of crunchy shell around a soft, chewy center.” (Bill Cheswick, Design of a Secure Internet Gateway, April, 1990) First firewalls deployed in Internet-connected organizations “Firewalls and Internet Security” published TIS toolkit commonly available Cisco buys PIX (Network Translation) CheckPoint revenues cross $100m WatchGuard introduces 1st FW appliance

Surely firewall makers have been busy since 1999 ? Clear market trends Faster Cheaper Smaller New Guard: NetScreen (Juniper), Watchguard, SonicWALL Old Guard: Cisco, Check Point Clear product trends Add VPN features Site-to-site Remote Access (?) Add policy-based URL control Websense-type Add interfaces No longer just inside, outside, DMZ

Surely, firewall makers have been busy since 1999 ? Clear market trends Faster Cheaper Smaller New Guard: NetScreen (Juniper), Watchguard, SonicWALL Old Guard: Cisco, Check Point Clear product trends Add VPN features Site-to-site Remote Access (?) Add policy-based URL control Websense-type Add interfaces No longer just inside, outside, DMZ

Incremental improvements are not very exciting Smaller, cheaper, faster: that’s great VPNs, more interfaces: that’s great But what have you done for me lately? To answer that, we need to digress to the oldest battle in all of firewall-dom: proxy versus packet filter!

Arguments between Proxy and Stateful PF continued Proxy More secure because you can look at application data stream More secure because you have independent TCP stacks Stateful PF Faster to write Faster to adapt Faster to run Faster also means cheaper

Proxy-based firewalls aren’t dead… just slow! Proxy Packet Filtering Src= Dst= TCP/IP Src= Dst= Kernel Inside network = /24 Outside net = RTL Process Space

Firewall Landscape: five years ago IBM eNetwork Secure Computing Altavista Firewall TIS Gauntlet Raptor Eagle Elron Cyberguard Ukiah Software NetGuard WatchGuard SonicWALL Check Point Livermore Software Milkyway Borderware Global Internet

Stateful Packet Filtering dominates the market Stateful Packet Filtering IP Kernel Check Point Cisco NetScreen SonicWALL Freeware-based products: Ipchains, IPF, Iptables, IPFW FW Newcomers: Fortinet, Toshiba, Ingate, ServGate, many others

But… the core argument was never disputed Proxy-based firewalls do have the possibility to give you more control because they maintain application- layer state information The reality is that proxy-based firewalls rarely went very far down that path Why? Market demand, obviously…

Firewall Evolution: What we hoped for… Additional granular controls on a wide variety of applications Intrusion detection and prevention functionality Vastly improved centralized management systems More flexible deployment options

Firewall Evolution: What we found… Additional granular controls on some a wide variety of applications Limited intrusion detection and prevention functionality Vastly improved centralized management systems More flexible deployment options Why? Market demand, obviously…

So what’s going on in the firewall business? Products are diverging, not converging Personalities of products are distinct IPS is a step forward, but not challenging the world of standalone products Rate of change of established products is slow compared to new entries

What does this mean for me and my firewall? Products are diverging Personalities are distinct IPS weaker than standalone Change rate slow Matching firewall to policy is hard; change in application or policy may mean changing product! Aggressive adoption of new features unlikely in popular products; need new blood to overcome product inertia

Are Intrusion Detection Systems dead? Massive Support from Marty Roesch, Ron Gula, Robert Graham Products from ISS, Cisco, and Tenable Cash and Prizes from Andy Briney and Neil Roiter

This is an IDS alert… IDS saw a packet aimed at a protected system IDS magic decoder technology correctly identifies this as “Back Orifice!”

This IDS alert ain’t no good Last time I checked, FreeBSD 4.9 was not one of the supported platforms for BackOrifice…

Please don’t call that a false positive IDS developers will jump down your throat “False Positive” means the IDS cried wolf when there was no such attack Usually the result of poorly written signatures Instead, let’s invent a complex multisyllable term: “non-contextual alert”

The IDS lacks “context” IF the IDS knew that the destination system was not running Windows… IF the IDS knew that the destination system was not running Back Orifice… IF the IDS knew that there was no such destination system… IF the IDS knew that the destination system was more hops away then TTL allowed…

IF IF IF the IDS knew more… THEN the IDS could tell the IDS operator more about this attack Ron Gula (Tenable) says that alerts are “raw intelligence.” They are data, but are not information yet. We need to turn them into “well-qualified intelligence” to start a war.

Roesch: “Target-Based IDS” Target-based IDS Sensor The sensor has knowledge about the network The sensor has knowledge about the hosts Target-based Event Correlation The output of the sensor is compared to knowledge of vulnerabilities Target-based IDS has two components

Start with a normal IDS… 1.IDS sensors generate enormous dinosaur-sized piles of alerts; alerts are sent to the IDS console 2.Operator gets enormous dinosaur-sized headache looking at hundreds of thousands of alerts … and add brains!

What does an IDS with brains look like?

Brains=knowledge + process Knowledge Somehow figure out lots of information about What systems are out there What software they are running What attacks they are vulnerable to Process Evaluate each alert with the additional contextual knowledge and decide To promote the alert To demote the alert That we don’t know

Can this quiet my IDS down? It could… But none of the products I looked at have a feedback loop to the IDS! Why don’t the scanners tell the IDS what ports to look on? Why don’t the scanners tell the IDS what signatures to ignore?

Is this right for you? YES! “I already have an IDS and I care about the alerts and I need some way to help prioritize them because I am drowning in alerts!” “I need to get an IDS for alerts but don’t have the manpower to analyze the alerts.” NO! “If I get this, my IDS will be a self-tuning smooth-running no- maintenance machine.” “I have no network security policy which says what to do when an alert occurs.”

Advanced Intrusion Defense Joel Snyder Opus One