Network Security

1. Dr. Subrata Goswami Aerogram Networks Fremont, CA Network Security

2. Overview • History • Current State • Current Efforts

3. History • For a long time network security implied cryptography to the R&D community (50-90). • Internet arrived with Web-browser and email – and the venerated Firewall and Virus Scanner appeared ( circa 1995). • The first Internet virus is Morris Worm in 1988. • FW in late 80’s (accredited to Steve Bellovin). • Trusted Information Systems (TIS) Firewall Toolkit (FWTK) 10/1/1993. • Checkpoint FW-1 in 1994. • McAfee Pro-scan 1990. • IPSec and SSL standardized (circa 1998). • Then Spam Filters, IDS and IPS. • AES standardized (2001), 3DES (1999), DES (1977). • WiFi WEP debacle prompted 802.11i (circa 2004) . • SHA-1 broken ? (2005).

4. The Current Issues • Virus, Spam, Worms, DOS/DDOS although tamed still exists. • Software vulnerabilities (bad/sloppy code). • Spyware/Adware • Peer-to-peer • Federal and Sate regulations: SOX, HIPPA, GLB, CA SB 1386, ITAR. • Phising, Social Engineering.

5. Current Industry Efforts(Partial List) • Network Access Control • Content Scanning • Traffic Profiling

6. Access Control - Cisco NAC EAP Over RADIUS AAA Server Vendor Policy Server EAP Over UDP/802.1x AV Agent HCAP Cisco ACS • Cisco Trust Agent • Communicate • EAP TLV • Auth (PEAP) • encryption Network Access Device Remediation 1. Triggers Intercept ACL on router, default ACL determines initial network access 2. Router triggers posture validation with CTA (EAPoUDP) 3. CTA sends posture credentials to router (EAPoUDP) 4. Router sends posture credentials to AAA (RADIUS) 5. If necessary, AAA request posture validation (HCAP - Host Credential Authorization Protocol (HTTPSbased)) 6. AAA validates posture (Healthy, Checkup, Quarantine, Remediate) 7. AAA sends Access-Accept with ACLs/URL redirect as per policy to router. 8. Host granted/denied/redirected/restricted access.

7. Access Control - Cisco NAC • Network Admission Control functionality enables Cisco routers to enforce access privileges when an endpoint (OS and AV patches) attempts to connect to a network. • Proprietary architecture • Proprietary Protocols – PEAP and HCAP. • Partners Symantec, McAfee, Trendmicro

8. Access Control - MAC-SEC • To provide user data confidentiality, frame data integrity, and data origin authenticity. HUB CA Discovery Peer Authentication Key Mgmt KaY D A B C SecY Protection SCA SCB SCC CAABC SC: Secure Channel CA: Connectivity Assoc

9. Access Control - MAC-SEC DST:6 SRC:6 SecureTAG:8/16 DATA ICV:8-16 Ether Type:2 TCI AN SL:1 PacketNumber:4 SCID:8 SRC MAC + Port > 2 peers SPI:4 SN:4 DATA:n PAD:0-255 PL:1 NH:1 ICV:n IPSEC ESP

10. Access Control - MAC-SEC (TX)

11. Access Control - MAC-SEC (RX)

12. Content Scanning • The problem is to find a hex sub-string in the continuous bytes of a flow. • Substantial theoretical research: Boyer-Moore, Aho-Corasick, • CPU MIPS required.

13. String Matching Algorithm • Knuth-Morris-Pratt • Boyer-Moore uses huresritcs to speed up. • O(k(m+n)) • Commentz-Walter • Wu-Manbar • Aho-Corasick creats an NFA( then a DFA) out all the search patterns. • O(n) • State explosion

14. COTS IP Packet Processor Architecture (IXP 2400 circa 2003) • 4 GE ports • Throughput • 4 Gbps for all frame sizes • 12 mpps for 64 byte frames • 0.4 mpps for 1518 byte frames • Latency : • 100% throughput 45 usec for 1518 byte frames. • 75% throughput 34 usec for 1518 byte frames. • 50% throughput 26 usec for 1518 byte frames. • 25% throughput 17.4 usec for 1518 byte frames.

15. 72 Stripe/byte align MEv2 1 MEv2 2 DDRAM Rbuf 64 @ 128B S P I 3 or C S I X 32b MEv2 4 MEv2 3 XScale Core 32K IC 32K DC G A S K E T PCI (64b) 66 MHz Tbuf 64 @ 128B 32b 64b MEv2 5 MEv2 6 Hash 64/48/128 Scratch 16KB CSRs -Fast_wr -UART -Timers -GPIO -BootROM/Slow Port QDR SRAM 1 QDR SRAM 2 MEv2 8 MEv2 7 E/D Q E/D Q 18 18 18 18 IXP2400 Internal Architecture 1 3 4 2

16. String Matching - MIPS Issue • DRAM packet buffer access speed = d (19.2 gbps). • Average packet size = b (1000 bits) • SRAM pattern access speed = s (12.8 gbps). • ME/CPU compares = c ( 0.600 gips) • Number of patterns = p (1000 ) • Average pattern length = l (100 bits) • Times each pattern read /packet = f1 (1 ,scratch memory) • Theoretical pattern matching rate • 1/( b/d + f1lp/s + blp/322c ) • 127Kpps • 5860 pps (worst case), 28654 pps (with tree/DFA)

17. String Matching - MIPS Issue(Content Processors) • 17 Gbps content search (Seaway Networks). • Stream based vs. packet based. • HW assists for content matching, modification, and replication. • 4.0 Gbps (Cavium Networks) • Multi-core architecture connected by SPI 4.2 (10 Gbps). • (Sensory Networks) • Origin in gene sequence search. • Matching against one pattern ? how long pattern ? What algorithm ?

18. String Matching Uses – IDS(SNORT) frag2 stream4 syslog http_decode sql portscan smb SPADE Preprocessor Detection Engine Log/Alert Engine Ouput Engine pcap rules Signature based Software content

19. String Matching Uses 1(SNORT) • Snort – Open source software IDS • Uses BM, AC, WM, Setwise BM • User space – substantial performance issue – I believe the best performance has been about 80 mbps on state of the art PC platforms. • String matching used for flagging viruses, spy wares, application vulnerabilities through signatures. • Also supports Regular Expressions – performance is an issues.

20. String Matching Use – Compliance(Reconnex)

21. String Matching Uses 2(Reconnex) • Content Security for compliance and IP protection. • Detects SSN, Credit Card Numbers etc. • Uses proprietary methods to generate signatures from repositories. • Signatures matched in as packets are streamed in. • Packets are assembled into flows and stored in hard disks for audit purposes. • PC platform , dual Pentium , 4 G RAM, 1.5TB HD.

22. Profiling • Profiled Items • Top Applications • Top Sources & Destinations • Top Conversations • Protocol Analysis • TCP state reconstruction • UDP/ICMP state reconstruction • Application protocols – FTP, Telnet, HTTP, Sun RPC, MSRPC, NFS, SMB/CIFS, P2P – Kazza, etc. • Tunneled – IPIP, HTTP

23. Profiling - Issues • Number of simultaneous flows (s) • Memory issue – typical per flow memory is 256 bytes. • Current products support ~ 5 millions flows. • Flow create rate ( c) • A pathological case is SYN attack. • Flow demise rate ( d) • Graceful demise ( e.g. 4-way TCP FIN hand shake). • Timeouts (e.g. SYN attack). • Steady State • c < d • average flow life < s/d

24. Profiling - Issues • Protocol state machine • both sides - client/server, requestor/responder, initiator/responder. • Time budget • CPU/NP/CP clock cycle time, tc (1.0 nsec). • Buffering memory available , M ( 1 GB ). • System throughput, tt( 2 Gbps). • Cycles per bit available, c. • c = M/(tc* tt)( 4 sec/1e9) ! - Not allowed, tolerable latency is << 150 ms. If 1.0 msec is allowed, then c is 1,000,000.

25. Profiling • Cisco Netflow (IPFIX), PSAMP • CAIDA • Mazu Networks • Imperva • Allot • Narus

26. Conclusion • Network Security, Information Security, is a very vibrant area - many players selling many products and services ( eerily similar to 1999). • Overheard – information security is a eternal gold mine.