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Defense-in-Depth, Part 2: Advanced Intrusion Defense. Joel Snyder Opus One [email protected]. Traditional perimeter technology is being…. … Supplemented? . Firewalls now have “advanced application intelligence” Actually, they had that already, but the marketroids had to keep themselves busy - PowerPoint PPT Presentation
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Defense-in-Depth, Part 2:Advanced Intrusion
DefenseJoel SnyderOpus [email protected]
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IDS has been replaced by IPS• (No, I don’t believe that, I’m just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 e-mail by a factor of 20 to 1 Spam represents 50% to 75% of all
e-mail 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
http://infosecuritymag.techtarget.com/
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)
1989 1991 1993 1995 1997 1999 2001 2003 2005
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
FasterCheaperSmaller • New Guard:
NetScreen (Juniper), Watchguard, SonicWALL
• Old Guard: Cisco, Check Point
Clear product trendsAdd 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 trendsFasterCheaperSmaller • New Guard:
NetScreen (Juniper), Watchguard, SonicWALL
• Old Guard: Cisco, Check Point
Clear product trendsAdd 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 greatVPNs, more interfaces: that’s greatBut 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
ProxyMore secure because you
can look at application data stream
More secure because you have independent TCP stacks
Stateful PFFaster to writeFaster to adaptFaster to runFaster also means
cheaper
Proxy-based firewalls aren’t dead… just slow!
Proxy
Packet Filtering
Src=10.1.1.99Dst=5.6.7.8
TCP/IP
Src=1.2.3.4Dst=5.6.7.8
Kernel
Inside network = 10.1.1.0/24
Outside net = 1.2.3.4
RTL
Process Space
Firewall Landscape: five years ago
IBM eNetworkSecure ComputingAltavista FirewallTIS GauntletRaptor EagleElronCyberguardUkiah Software
NetGuardWatchGuardSonicWALLCheck PointLivermore SoftwareMilkywayBorderwareGlobal Internet
Stateful Packet Filtering dominates the market
Stateful Packet Filtering
IP
Kernel
Check PointCisco 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 pathWhy? 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 somea 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 convergingPersonalities of products are distinct IPS is a step forward, but not challenging the world of
standalone productsRate 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?
http://infosecuritymag.techtarget.com/
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 + processKnowledge
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 DefenseJoel SnyderOpus One