Application-layer firewalling: Raise your perimeter IQ Joel Snyder Opus One Acknowledgements • 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) First firewalls deployed in Internet-connected organizations TIS toolkit commonly available “Firewalls and Internet Security” published Cisco buys PIX (Network Translation) CheckPoint revenues cross $100m WatchGuard introduces 1st FW appliance 1989 1991 1993 1995 1997 1999 2001 2003 2005 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 Shirley 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 Process Space RTL TCP/IP Inside network = 10.1.1.0/24 Outside net = 1.2.3.4 Src=1.2.3.4 Dst=5.6.7.8 Src=10.1.1.99 Dst=5.6.7.8 Packet Filtering Kernel 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 Check Point Cisco NetScreen SonicWALL Freeware-based products: Ipchains, IPF, Iptables, IPFW FW Newcomers: Fortinet, Toshiba, Ingate, Enterasys, many others IP Stateful Packet Filtering Kernel 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 • Vastly improved centralized management systems • Intrusion detection and prevention functionality • 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… Additional Granular Controls focused on a few applications • Everybody loves HTTP management Header filtering File type & MIME type blocking Embedded Data blocking (Javascript) Virus scanning, URL Filtering • Other applications are piecemeal FTP SMTP VoIP File Sharing HTTP-oriented features served “pressure points” HTTP Action Controls Filename & MIME type blocking Header Filtering SOAP controls URL Translation Post/Put/ Delete Filename; no MIME blocking Full Basic Yes Netscreen None Filename .EXE & .ZIP; no MIME blocking No No No WatchGuard Post MIME blocking Limited Set No No ActiveX, Java ActiveX, Java, Cookies CyberGuard Symantec Can block 'upload' only Filename & MIME type blocking Filename blocking by extension Check Point Get/Post/ Put/Head Filename by wildcard; no MIME blocking SecureComputing All Can Block within HTTP… ActiveX, Java, Javascript, VBScript, XML Virus detection URL filtering/ blocking Yes, external server WebSense Yes, internal or external server WebSense plus local URL list None Local scanning, 2 types (signature/he uristic) WebBlocker Full Block/Allow No ActiveX, Java, Javascript, VBScript No No No WebDAV, DCOM Local scanning Smartfilter and local URL list Rating system and local URL list Yes ActiveX, Java, Javascript, Vbscript Yes, external server OPSEC and local URL list Full Basic Advanced Controls are diverse across products FTP H.323 Product • • CyberGuard • Netscreen • WatchGuard • Secure Computing • • • Symantec • • Check Point HTTP LDAP NNTP RealAudio • • • • • • • • • • • SIP SMTP POP DNS IMAP Socks • • • • • • • • • • • • • SNMP CIFS • •Differentiating between “advanced” controls and “basic” controls was easy to do. •Proxy-based firewalls proved to be almost undistinguishable from their “insecure” stateful packet filtering brethren. •Vendors appear to be reactive, not proactive. • • Virus Scans and Policy Controls are simple, right? • No! Some firewalls insisted on having virus and/or URL scanning happen “off box” • No! Some firewalls can’t configure where you scan for viruses • No! Some devices don’t have virus scanning • No! Some firewalls don’t support a local list of blocked URLs Conclusion: it’s not simple We’ve learned how to write good GUIs, haven’t we? • Not in the firewall business, we haven’t • Additional granularity means additional thinking about resources • Products are … disappointing The firewall people have a lot to learn from the SSL VPN people Centralized management has improved a bit • Folks who had it are doing slightly better than they were • Folks who didn’t have it now generally have something We’re still missing a general policy management system for firewalls Many of the centralized management tools have very rough edges “Intrusion” is the new buzzword in security Rate-based IPS Content-based IPS technology technology • In firewalls, means • Based on IDS-style “SYN flood protection” thinking • May be smart (NS) • May have small signature base (NS, • May include shunning CP) (SecComp, WG, CP) • May be an “IDS with the IPS bit on” (Symantec) 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 • Matching firewall to policy is hard; change in application or policy may mean changing product! • IPS weaker than standalone • Change rate slow • Aggressive adoption of new features unlikely in popular products; need new blood to overcome product inertia Application-layer firewalling Joel Snyder Opus One Member, Information Security Magazine test alliance jms@opus1.com Questions Submit your questions to Joel by clicking on the Ask a Question link on the lower left corner of your screen. 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